Wrist Articulation by Linked Tension Members

ABSTRACT

Surgical tools having a two degree-of-freedom wrist, wrist articulation by linked tension members, mechanisms for transmitting torque through an angle, and minimally invasive surgical tools incorporating these features are disclosed. An elongate intermediate wrist member is pivotally coupled with a distal end of an instrument shaft so as to rotate about a first axis transverse to the shaft, and an end effector body is pivotally coupled with the intermediate member so as to rotate about a second axis that is transverse to the first axis. Linked tension members interact with attachment features to articulate the wrist. A torque-transmitting mechanism includes a coupling member, coupling pins, a drive shaft, and a driven shaft. The drive shaft is coupled with the driven shaft so as to control the relative orientations of the drive shaft, the coupling member, and the driven shaft.

CROSS-REFERENCES TO RELATED APPLICATIONS

The present application is a Continuation of U.S. patent applicationSer. No. 12/945,730 filed Nov. 12, 2010 (Allowed); which applicationclaims the benefit of U.S. Provisional Application Nos. 61/260,903 filedNov. 13, 2009; 61/260,910 filed Nov. 13, 2009; and 61/260,915 filed Nov.13, 2009; 61/260,907 filed Nov. 13, 2009; and 61/260,919 filed Nov. 13,2009; the full disclosures of which are incorporated herein byreference.

BACKGROUND

Minimally invasive surgical techniques are aimed at reducing the amountof extraneous tissue that is damaged during diagnostic or surgicalprocedures, thereby reducing patient recovery time, discomfort, anddeleterious side effects. As a consequence, the average length of ahospital stay for standard surgery may be shortened significantly usingminimally invasive surgical techniques. Also, patient recovery times,patient discomfort, surgical side effects, and time away from work mayalso be reduced with minimally invasive surgery.

A common form of minimally invasive surgery is endoscopy, and a commonform of endoscopy is laparoscopy, which is minimally invasive inspectionand/or surgery inside the abdominal cavity. In standard laparoscopicsurgery, a patient's abdomen is insufflated with gas, and cannulasleeves are passed through small (approximately one-half inch or less)incisions to provide entry ports for laparoscopic instruments.

Laparoscopic surgical instruments generally include an endoscope (e.g.,laparoscope) for viewing the surgical field and tools for working at thesurgical site. The working tools are typically similar to those used inconventional (open) surgery, except that the working end or end effectorof each tool is separated from its handle by an extension tube (alsoknown as, e.g., an instrument shaft or a main shaft). The end effectorcan include, for example, a clamp, grasper, scissor, stapler, cauterytool, linear cutter, or needle holder.

To perform surgical procedures, the surgeon passes working tools throughcannula sleeves to an internal surgical site and manipulates them fromoutside the abdomen. The surgeon views the procedure from a monitor thatdisplays an image of the surgical site taken from the endoscope. Similarendoscopic techniques are employed in, for example, arthroscopy,retroperitoneoscopy, pelviscopy, nephroscopy, cystoscopy, cisternoscopy,sinoscopy, hysteroscopy, urethroscopy, and the like.

Minimally invasive telesurgical robotic systems are being developed toincrease a surgeon's dexterity when working on an internal surgicalsite, as well as to allow a surgeon to operate on a patient from aremote location (outside the sterile field). In a telesurgery system,the surgeon is often provided with an image of the surgical site at acontrol console. While viewing a three dimensional image of the surgicalsite on a suitable viewer or display, the surgeon performs the surgicalprocedures on the patient by manipulating master input or controldevices of the control console. Each of the master input devicescontrols the motion of a servo-mechanically actuated/articulatedsurgical instrument. During the surgical procedure, the telesurgicalsystem can provide mechanical actuation and control of a variety ofsurgical instruments or tools. Many of the telesurgical tools have jawsor other articulatable end effectors that perform various functions forthe surgeon, for example, holding or driving a needle, grasping a bloodvessel, dissecting tissue, or the like, in response to manipulation ofthe master input devices. Tools having distal wrist joints allow thesurgeon to orient the tool within the internal surgical site, greatlyenhancing the freedom with which the surgeon can interact with (andtreat) the tissue in real time.

Telesurgical systems are finding increasing applications by surgeons forgrowing variety of therapies. New tools would help to continue thisgrowth, and particularly tools such as staplers, linear cutters, and thelike (which are capable of imposing significant clamping and otherforces against the internal tissues). Unfortunately, it can bechallenging to transmit the desired telesurgical end effector forcesthrough known tool wrists, particularly while retaining the responsetime, precision, flexibility, and reliability in the tool that isdesired for telesurgical tasks.

For example, non-robotic surgical tools comprising linear clamping,cutting, and stapling devices have been employed in many differentsurgical procedures. Such a tool can be used to resect a cancerous oranomalous tissue from a gastro-intestinal tract. Unfortunately, manyknown surgical tools, including known linear clamping, cutting, andstapling tools, lack the ability to transmit desired torques (e.g.,tissue clamping torque) or forces (e.g., staple firing force) across acompact articulated wrist, which may reduce the effectiveness of thesurgical tool. Alternative tools with a shaft driven clamping mechanismalso fail to provide rotational movement of an end effector to mimic thenatural action of a surgeon's wrist.

For the reasons given above, it is desirable to provide improvedsurgical and/or robotic wrist structures. It would also be desirable toprovide improved minimally invasive surgical tools that include a wristmechanism that mimics the natural action of a surgeon's wrist, whileallowing enhanced end effector forces and a response time suitable fortelesurgical control.

BRIEF SUMMARY

Surgical tools with a two degree-of-freedom wrist, and related methods,are provided. The disclosed surgical tools may be particularlybeneficial when used in minimally invasive surgery. In many embodiments,an intermediate wrist member is pivotally coupled with a distal end ofan instrument shaft so as to rotate about a first axis transverse to theshaft, and an end effector body is pivotally coupled to the intermediatemember so as to rotate about a second axis transverse to the first axis.Such a two degree-of-freedom wrist can be used to articulate the endeffector body in a way that mimics the natural action of a surgeon'swrist, thereby providing a desirable amount of maneuverability for theend effector body. In many embodiments, the intermediate member has anelongate shape. An elongate shape leaves adjacent areas free for therouting of actuation components, for example, actuation components thatarticulate the end effector body relative to the instrument shaft, andactuation components (e.g., control cables, drive shafts) thatarticulate one or more end effector features relative to the endeffector body. In many embodiments, the two degree-of-freedom wristincludes internal passages for guiding control cables. Such internalpassages can be configured to inhibit altering control cable tensionsduring pivoting about the first and second axes.

Exemplary embodiments provide wrist articulation via linked tensionmembers. In many embodiments, an end effector is coupled with a distalend of an elongate shaft via a two degree-of-freedom joint so as toallow the end effector to be oriented within an internal surgical space.In the exemplary embodiments, opposed movements of tension membersangularly orient the end effector relative to the shaft, and slidinginterface surfaces between the tension members and the end effector varypositions of the tension members in correlation with the orientation ofthe end effector to inhibit undesirable changes in tension of thetension members. By inhibiting such changes in tension of the tensionmembers, detrimental control cable slack and/or overstressing ofsurgical tool components may be avoided when the tension members areused as linked pairs, for example, with opposed tension members sharinga common linear drive mechanism (e.g., a motor driven capstan).Actuating the tension members in linked pairs may provide for smooth andresponsive articulation of the end effector relative to the shaft. Wristarticulation by linked tension members can also be used to reduce thelength of the surgical tool distal of the shaft, which may improveaccess in a confined body space, angle of access to body structures, andvisibility of body structures.

Mechanisms for transmitting torque through an angle, minimally invasivesurgical tools comprising a mechanism for transmitting torque through anangle, and related methods are also provided. The disclosed mechanismscan be used, for example, to transmit torque to a shaft driven actuationmechanism of a surgical end effector that is mounted to an instrumentshaft via a two degree-of-freedom wrist. In many surgical applications(e.g., many minimally invasive surgical applications) it may bebeneficial to use a surgical tool comprising a surgical end effectormounted to the distal end of an instrument shaft via a twodegree-of-freedom wrist so as to mimic the (often relatively rapid)natural action of a surgeon's wrist. By actuating the end effector witha rotational shaft drive, a high level of force can be applied totissues through a narrow shaft. For example, such a shaft drivenmechanism can be used to articulate a clamping jaw of the end effectorso as to generate a high clamping force. Exemplary embodiments cantransmit sufficient torque through the angled wrist of a minimallyinvasive surgical tool using a relatively simple dual ball-and-socketjoint system in which the ball ends are coupled together to constrainthe socket angle, and in which pins traversing the sockets transfertorque. This simple arrangement lends itself to miniaturization for usein, for example, a surgical instrument. This simple arrangement may alsoimprove the reliability of tools that transmit torque through anglesexceeding 60 degrees, thereby allowing substantial reorientation of anend effector relative to an instrument shaft. In many embodiments, arate of rotation of a drive shaft and a driven shaft are substantiallyequal even when the drive shaft and the driven shaft are non-parallel,which may help provide smooth transmission of torque through the angle.

In a first aspect, a minimally invasive surgical tool is provided. Thesurgical tool includes a tubular instrument shaft having a proximal endand a distal end with a bore there between, an end effector including anend effector body; an intermediate wrist member pivotally coupled withthe distal end of the shaft and pivotally coupled with the end effectorbody; and an actuation system extending distally through the bore of theshaft so as to orient the end effector body and actuate the endeffector. The instrument shaft has an instrument-shaft axis. Pivoting ofthe intermediate body relative to the shaft orients intermediate memberabout a first axis relative to the shaft. Pivoting of the end effectorbody relative to the intermediate member orients the end effector bodyabout a second axis relative to the intermediate member. The first axisis transverse to the shaft axis. The second axis is transverse to thefirst axis. The intermediate member has an exterior width along thefirst axis and an exterior length along the second axis. The length issignificantly different than the width so that the intermediate memberhas an elongate cross section. A portion of the actuation system islaterally separated from the elongate cross section of the intermediatemember between the shaft and the end effector body.

The intermediate member can include one or more additional featuresand/or characteristics. For example, the width of the intermediatemember can be less than one-fourth the length of the intermediatemember. The first axis and the second axis can be within 2 mm of beingcoplanar. The first axis and the second axis can be coplanar. Theintermediate member can include internal passages for guiding controlcables of the actuation system between the instrument shaft and the endeffector body.

The surgical tool can include one or more additional features and/orcharacteristics. For example, the surgical tool can include a firstjoint pivotally coupling the shaft to the intermediate member and asecond joint pivotally coupling the intermediate member to the endeffector body. The first joint can include a single pivot shaftextending along the first axis within the width of the intermediatemember so that the first joint is disposed within a central regionbetween the shaft and the end effector body clear of the laterallyseparated portion of the actuation system. The second joint can includefirst and second coaxial pivot shafts separated along the second axis.The intermediate member can include internal passages for guidingcontrol cables of the actuation system between the instrument shaft andthe end effector body and between the coaxial pivot shafts of the secondjoint. The surgical tool can include a support member fixedly coupledwith the instrument shaft and pivotally coupled with the intermediatemember for rotation about the first axis. The support member can includeinternal passages for guiding control cables of the actuation systemrouted between a bore of the instrument shaft and the end effector body.The guide surfaces can constrain the control cables so as to inhibitaltering cable tensions during pivoting about the first and second axes.

The actuation system can include one or more additional features and/orcharacteristics. For example, the laterally separated portion of theactuation system can include a first rotatable drive shaft for driving afirst actuation mechanism of the end effector. The first drive shaft canbe routed between the end effector body and the bore so as to passadjacent to a first side of the intermediate member. The laterallyseparated portion of the actuation system can include a second rotatabledrive shaft for driving a second actuation mechanism of the endeffector. The second drive shaft can be routed between the end effectorbody and the bore so as to pass adjacent to a second side of theintermediate member, the second side being opposite the first side. Anorientation portion of the actuation system can be operable to vary theorientation of the end effector body relative to the instrument shaftabout the first and second axes. The orientation portion can be backdrivable so that forces applied to the end effector body so as to alterits orientation are transmitted proximally through the bore by theactuation system. An actuation of the end effector can includearticulation of a joint of the end effector.

In another aspect, a method for manufacturing a minimally invasivesurgical tool is provided. The method includes pivotally coupling anintermediate member to an instrument shaft for rotation about a firstaxis oriented non-parallel to an elongate direction of the instrumentshaft, pivotally coupling an end effector to the intermediate member forrotation about a second axis oriented non-parallel to the first axis andthe elongate direction, and coupling an actuation mechanism with the endeffector. The actuation mechanism is operable to vary the orientation ofthe end effector relative to the elongate direction in two dimensions.At least a portion of the actuation mechanism is routed between the endeffector and a bore of the instrument shaft so as to pass outside of andseparated from at least one side of the intermediate member.

In the method for manufacturing a minimally invasive surgical tool, theintermediate member coupled to the instrument shaft, and to which theend effector is coupled, can include one or more additional featuresand/or characteristics. For example, the first axis can be normal to thesecond axis. At least one of the first axis or the second axis can benormal to the instrument-shaft elongate direction. The intermediatemember can have an exterior width in the first-axis direction and amaximum exterior length in the second-axis direction that is greaterthan the width in the first-axis direction. The intermediate member canhave a maximum exterior width in the first-axis direction that is lessthan one-third of the exterior length. In intermediate member caninclude internal passages for guiding control cables routed between theend effector and a bore of the instrument shaft. The guide surfaces canconstrain the control cables so as to inhibit altering cable tensionsduring pivoting about the first and second axes.

The method can include further steps. For example, the method canfurther include routing end effector control cables throughintermediate-member internal passages. The method can further includeback driving the actuation mechanism by varying the orientation of theend effector relative to the instrument shaft so that forces applied tothe end effector so as to alter its orientation are transmittedproximally through the bore by the actuation system. Actuation of theend effector can include articulating a joint of the end effector.

In another aspect, a minimally invasive surgical method is provided. Themethod includes inserting a surgical end effector of a tool to aninternal surgical site via a minimally invasive aperture or naturalorifice, pivoting an intermediate member of the tool relative to a shaftof the tool about a first joint so as to orient the intermediate memberabout a first axis relative to the shaft of the tool supporting the endeffector, pivoting the end effector relative to the intermediate memberabout a second joint so as to orient the end effector about a secondaxis relative to the intermediate member, mechanically actuating the endeffector with an actuation-system component that passes between the boreand the end effector laterally offset from a central joint. One of thefirst joint and the second joint includes the central joint, which is acentrally located joint disposed within a central portion of a crosssection of the tool. In the method, an actuation of the end effector caninclude articulating a joint of the end effector.

In another aspect, a minimally invasive surgical tool is provided. Thesurgical tool includes an elongate first link, a second link, fourattachment features disposed on the second link, and four tensionmembers. The elongate first link has a distal end, a proximal end, and afirst link axis defined there between. The first link has an axial bore.The second link is pivotally coupled with the distal end of the firstlink so as to orient the second link about a first axis and a secondaxis. The first and second axes are nonparallel to the first link axis.The first axis is nonparallel to the second axis. The four tensionmembers extend distally from within the bore of the first link to theattachment features so that opposed axial movement of the tensionmembers angularly orients the second link relative to the first linkabout the first and second axes. Interface surfaces between the tensionmembers and the attachment features vary the positions of the tensionmembers relative to the second link in correlation with angularorientations of the second link relative to the first link so as toinhibit changes in tension of the tension members.

The first and second axes can have one or more additionalcharacteristics. For example, the first and second axes can benon-intersecting. The first and second axes can be separated by variousdistances, for example, by 2 mm or less. The first axis can betransverse to the first link axis and the second axis can be transverseto the first axis.

Each of the tension members can interact with a corresponding attachmentfeature so as to selectively constrain the motion of the tension member.For example, each of the tension members can pivot about a firstassociated center relative to one of the attachment features when thesecond link pivots about the first axis. Each of the tension members canpivot about a second associated center relative to one of the attachmentfeatures when the second link pivots about the second axis. The tensionmembers can slidingly engage the attachment features. The interfacesurfaces can include curving cylindrical surfaces having circularcross-sections and curving interface axes, the circular cross-sectionsdefining cross-sectional centers and the curving interface axes definingcenters of curvature. Each of the first and second associated centerscan correspond to a cross-sectional center or a center of curvature.

The attachment features can comprise a curved portion. For example, eachof the attachment features can comprise a curved portion. Each of thetension members can comprise an attachment lug configured to slidinglyreceive one of the curved portions so as to slide against and along thecurved portion when the second link pivots about one of the first andsecond axes. Each of the curved portions can comprise a centerline thatlies in a plane perpendicular to the first axis or the second axis. Eachof the curved portions can have a first radius of curvature about itscurved centerline and a fixed center of curvature for its curvedcenterline. Each of the fixed centers of curvature can lie in a planecontaining at least one of the first axis or the second axis. Each ofthe curved portion centerlines can be tangent to a plane containing atleast one of the first axis or the second axis.

The attachment features can comprise an attachment lug. For example,each of the attachment features can comprise an attachment lug. Each ofthe tension members can comprise a curved portion configured to beslidingly received by one of the attachment lugs so that the curvedportion slides within the attachment lug when the second link pivotsabout one of the first and second axes. Each of the attachment lugs canhave a connection hole axis oriented parallel to the first axis or thesecond axis. Each connection hole axis can lie in a plane containing atleast one of the first axis or the second axis. Each of the curvedportions can comprise a curved centerline that lies in a planeperpendicular to the first axis or the second axis. Each of the curvedportions can have a first radius of curvature about its curvedcenterline and a fixed center of curvature for its curved centerline.Each of the fixed centers of curvature can lie in a plane containing atleast one of the first axis or the second axis. Each of the curvedportion centerlines can be tangent to a plane containing at least one ofthe first axis or the second axis.

Diagonally opposed tension members can be paired together and actuatedin common. For example, each of the attachment features can be offsetfrom the first and second axes when viewed along the first link axis,with one of the attachment features being disposed in each quadrantdefined by the first and second axes when viewed along the first linkaxis. A first diagonally opposed pair of the tension members can beactuated by at least one cable extending from a first tension member ofthe first diagonally opposed pair to a second tension member of thefirst diagonally opposed pair, with the at least one cable being wrappedaround a first capstan. Varying positions of the first diagonallyopposed pair of the tension members relative to the second link caninhibit variations in tension of the at least one cable which would beimposed if the tension members were coupled to the attachment featureswith spherical center joints. A second diagonally opposed pair of thetension members can be actuated by at least one cable extending from afirst tension member of the second diagonally opposed pair to a secondtension member of the second diagonally opposed pair, with the at leastone cable being wrapped around a second capstan. Varying positions ofthe second diagonally opposed pair of the tension members relative tothe second link can inhibit variations in tension of the at least onecable which would be imposed if the tension members were coupled to theattachment features with spherical center joints. The first diagonallyopposed pair of the tension members is different from the seconddiagonally opposed pair of the tension members, and the second capstanis different from the first capstan.

In another aspect, a surgical tool is provided. The surgical toolcomprises an elongate first link, a plurality of control cables, asecond link, and a plurality of interface assemblies. The elongate firstlink has a distal end, a proximal end, and a first link axis definedthere between. The first link has an axial bore. The plurality ofcontrol cables extends distally within the bore of the first link from acontrol cable actuation assembly disposed adjacent the proximal end ofthe first link. The second link is pivotally coupled with the distal endof the first link so as to orient the second link about a first axis anda second axis. The first and second axes are nonparallel to the firstlink axis. The first axis is nonparallel to the second axis. Eachinterface assembly couples one of the control cables with the secondlink so that axial movement of the control cables angularly orients thesecond link relative to the first link about the first and second axes.One of the interface assemblies comprises a length of curved portion andan attachment lug having an attachment lug hole sized to slidinglyreceive the curved portion. The attachment lug rotates about the curvedportion when the second link rotates about the first axis and slidesagainst and along the curved portion when the second link rotates aboutthe second axis.

In many embodiments, the plurality of control cables comprises fourcontrol cables. Each of the interface assemblies can comprise a lengthof curved portion and an attachment lug having an attachment lug holesized to slidingly receive the curved portion such that the attachmentlug rotates about the curved portion when the second link rotates aboutthe first axis and slides against and along the curved portion when thesecond link rotates about the second axis.

In another aspect, a method for manufacturing a surgical tool isprovided. The method comprises pivotally coupling a second link to afirst link to rotate about a first axis oriented non-parallel to anelongate direction of the first link and to rotate about a second axisoriented non-parallel to both the elongate direction of the first linkand the first axis, coupling a tension member with each of fourattachment features disposed on the second link, and coupling each ofthe tension members with an actuation mechanism operable to control theangular orientation of the second link relative to the first link in twodimensions by actuating the tension members. Each of the attachmentfeatures is offset from the first and second axes when viewed along theelongate direction of the first link. One of the attachment features isdisposed in each quadrant defined by the first and second axes whenviewed along the elongate direction of the first link. Each of thetension members extends distally from within the bore of the first linkto one of the attachment features of the second link so that axialmovement of the tension members angularly orients the second linkrelative to the first link about the axes. Interface surfaces betweenthe tension members and the attachment features vary a position of thetension members relative to the second link in correlation with theangular orientation of the second link relative to the first link so asto inhibit changes in tension of the tension members.

Coupling each of the tension members with an actuation mechanism cancomprise additional steps, for example, coupling a first tension memberof the tension members with a first control cable. A second tensionmember of the tension members can be coupled with a second controlcable, where the second tension member is diagonally opposite to thefirst tension member. The first and second control cables can be coupledwith a first capstan of the actuation mechanism. A third tension memberof the tension members can be coupled with a third control cable. Afourth tension member of the tension members can be coupled with afourth control cable, where the fourth tension member is diagonallyopposite to the third tension member. The third and fourth controlcables can be coupled with a second capstan of the actuation mechanism.

In another aspect, a surgical instrument is provided. The surgicalinstrument comprises a first link, a second link comprising anattachment feature, a joint that couples the first and second links, anda tension member comprising an attachment lug. The attachment featurecomprises a curved portion. The joint rotates around a first axisdefined in a first plane and around a second axis defined in a secondplane. The first and second planes are parallel to and offset from oneanother. The attachment lug is coupled to the attachment feature. Theattachment lug rotates around the curved portion when the tension memberrotates the joint around the first axis. The attachment lug slidesagainst and along the curved portion when the actuation member rotatesthe joint around the second axis.

In another aspect, a mechanism for transmitting torque through an angleis provided.

The mechanism includes a coupling member comprising a first end and asecond end with a coupling axis defined there between, a coupling pin, adrive shaft having a drive axis and a distal end, and a driven shafthaving a proximal end and a driven axis. The first end of the couplingmember comprises a receptacle. The coupling pin extends across thereceptacle. The drive shaft distal end is received within thereceptacle. The drive shaft distal end comprises a slot receiving thecoupling pin throughout a range of angles between the coupling axis andthe drive axis so that rotation of the drive shaft produces rotation ofthe coupling member via the coupling pin. The proximal end of the drivenshaft coupled with the second end of the coupling member so thatrotation of the coupling member about the coupling axis producesrotation of the driven shaft about the driven axis. The drive shaft iscoupled with the driven shaft so as to maintain corresponding anglesbetween the drive axis and the coupling axis, and the driven axis andthe coupling axis when an angle between the drive axis and the drivenaxis varies during rotation of the shafts.

A mechanism for transmitting torque through an angle can include one ormore additional features and/or can have one or more additionalcharacteristics. For example, the mechanism can further comprise a crosspin to couple the drive shaft with the coupling pin. The cross pin canbe oriented transverse to the coupling pin and mounted for rotationrelative to the drive shaft. An outer surface of the drive shaft distalend can comprise a spherical surface. The outer surface of the driveshaft can interface with the receptacle of the coupling member so as toaxially constrain the drive shaft and receptacle relative to each otherduring spherical pivoting there between. The receptacle can comprise aspherical surface that interfaces with the drive shaft sphericalsurface. The drive shaft distal end can comprise a set of spherical gearteeth and the driven shaft proximal end can comprise a set of sphericalgear teeth interfacing with the drive shaft gear teeth so as to maintainsubstantially equivalent angles between the drive axis and the couplingaxis, and the driven axis and the coupling axis. In many embodiments, atleast one of the drive shaft and the drive shaft gear teeth or thedriven shaft and the driven shaft gear teeth are integrally formed. Inmany embodiments, the mechanism is operable to transmit torque throughan angle exceeding 60 degrees.

In another aspect, a mechanism for transmitting torque through an angleis provided. The mechanism includes a drive shaft having a distal endand a drive axis, a driven shaft having a proximal end and a drivenaxis, and a coupling member coupled with each of the drive shaft distalend and the driven shaft proximal end so that rotation of the driveshaft about the drive axis produces rotation of the driven shaft aboutthe driven axis. At least one of the drive shaft distal end or thedriven shaft proximal end comprises a protrusion. The coupling membercomprises a tubular structure defining a drive receptacle and a drivenreceptacle with a coupling axis defined there between. At least one ofthe drive receptacle or the driven receptacle comprises a slotconfigured to receive the at least one protrusion and accommodate the atleast one protrusion through a range of angles between the drive shaftand the driven shaft. The protrusion interacts with the slot so as totransfer rotational motion between the drive shaft and the driven shaft.The drive shaft distal end engages the driven shaft proximal end so asto maintain corresponding angles between the drive axis and the couplingaxis, and the driven axis and the coupling axis when an angle betweenthe drive axis and the driven axis varies during rotation of the shafts.In many embodiments, the mechanism is operable to transmit torquethrough an angle exceeding 60 degrees.

In many embodiments, the drive shaft and the driven shaft interface withthe coupling member so that the drive shaft and the driven shaft areconstrained relative to the coupling member. For example, each of thedrive shaft distal end and the driven shaft proximal end can comprise anouter surface interfacing with the drive receptacle and the drivenreceptacle, respectively, such that, for each shaft, an intersectionpoint defined between the shaft axis and the coupling axis is axiallyaffixed along the shaft axis and along the coupling axis. The outersurfaces of the drive shaft distal end and the driven shaft proximal endcan comprise a spherical surface. The drive receptacle and the drivenreceptacle can comprise a spherical surface.

In many embodiments, the drive shaft distal end and the driven shaftproximal end comprise interfacing gear teeth. For example, the driveshaft distal end can comprise a drive shaft gear tooth surface extendingaround the drive axis, the driven shaft proximal end can comprise adriven shaft gear tooth surface extending around the driven axis, andthe drive shaft gear tooth surface can engage the driven shaft geartooth surface so as maintain correspondence between the angles. In manyembodiments, at least one of the drive shaft and the drive shaft geartooth surface or the driven shaft and the driven shaft gear toothsurface are integrally formed. In many embodiments, the drive shaft geartooth surface is defined by a drive shaft gear tooth profile extendingradially from the drive axis, the driven shaft gear tooth surface isdefined by a driven shaft gear tooth profile extending radially from thedriven axis, and the drive shaft gear tooth surface engages the drivenshaft gear tooth surface so as maintain substantial equivalence betweenthe drive/coupler angle and the driven/coupler angle. In manyembodiments, the drive shaft gear tooth surface comprises a revolutesurface defined by rotating the drive shaft gear tooth profile about thedrive axis, and the driven shaft gear tooth surface comprises a revolutesurface defined by rotating the driven shaft gear tooth profile aboutthe driven axis.

In another aspect, a minimally invasive surgical tool is provided. Thesurgical tool includes an instrument shaft, a drive shaft having adistal end and a drive axis, a driven shaft having a proximal end and adriven axis, a coupling member coupling the drive shaft with the drivenshaft so that a rate of rotation of the drive and driven shafts aresubstantially equal when the drive axis and the driven axis arenon-parallel, and an end effector coupled with the instrument shaft sothat an orientation of the end effector can be varied in two dimensionsrelative to the instrument shaft. The drive shaft is mounted forrotation within the instrument shaft. The end effector comprises anarticulated feature coupled with the driven shaft so that a rotation ofthe driven shaft about the driven axis produces an articulation of thefeature.

In many embodiments, the drive shaft is axially and rotationally coupledwith the coupling member, the driven shaft is axially and rotationallycoupled with the coupling member, and the drive shaft engages the drivenshaft. For example, the coupling member can comprise a first end and asecond end with a coupling axis defined there between and the driveshaft distal end can be axially and rotationally coupled with thecoupling member first end so that rotation of the drive shaft about thedrive axis produces rotation of the coupling member about the couplingaxis. The driven shaft proximal end can be axially and rotationallycoupled with the coupling member second end so that rotation of thecoupling member about the coupling axis produces rotation of the drivenshaft about the driven axis. The drive shaft distal end can engage thedriven shaft proximal end so as to maintain corresponding angles betweenthe drive axis and the coupling axis, and the driven axis and thecoupling axis when an angle between the drive axis and the driven axisvaries during rotation of the shafts. The drive shaft distal end cancomprise spherical gear teeth and the driven shaft proximal end cancomprise spherical gear teeth engaging the drive shaft gear teeth. Inmany embodiments, at least one of the drive shaft and the drive shaftgear teeth or the driven shaft and the driven shaft gear teeth areintegrally formed.

In many embodiments, the tool further comprises a coupling pin couplingthe coupling member with the drive shaft so as to transfer rotationalmotion between the drive shaft and the coupling member. For example, thetool can further comprise a coupling member first end receptacle, acoupling pin crossing the receptacle, a drive shaft distal end outersurface interfacing with the receptacle, and a drive shaft distal endslot receiving the coupling pin throughout a range of angles between thecoupling axis and the drive axis. Interaction between the coupling pinand the slot can couple the drive shaft with the coupling member so thatrotation of the drive shaft produces rotation of the coupling member.The mechanism can further comprise a cross pin to couple the drive shaftwith the coupling pin. The cross pin can be oriented transverse to thecoupling pin and mounted for rotation relative to the drive shaft.

In many embodiments, at least one of the drive shaft distal end or thedriven shaft proximal end comprises a protrusion. The coupling membercan comprise a tubular structure defining a drive receptacle and adriven receptacle along the coupling axis and at least one of the drivereceptacle or the driven receptacle can comprise a slot configured toreceive the protrusion and accommodate the protrusion through a range ofangles between the drive axis and the driven axis. The protrusion caninteract with the slot so as to transfer rotational motion between atleast one of the drive shaft or the driven shaft and the couplingmember.

For a fuller understanding of the nature and advantages of the presentinvention, reference should be made to the ensuing detailed descriptionand accompanying drawings. Other aspects, objects and advantages of theinvention will be apparent from the drawings and detailed descriptionthat follows.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a plan view of a minimally invasive robotic surgery systembeing used to perform a surgery, in accordance with many embodiments.

FIG. 2 is a perspective view of a surgeon's control console for arobotic surgery system, in accordance with many embodiments.

FIG. 3 is a perspective view of a robotic surgery system electronicscart, in accordance with many embodiments.

FIG. 4 is a simplified diagrammatic illustration of a robotic surgerysystem, in accordance with many embodiments.

FIG. 5a is a front view of a patient-side cart (surgical robot) of arobotic surgery system, in accordance with many embodiments.

FIG. 5b is a front view of a robotic surgery tool.

FIG. 6 is a perspective view of a two degree-of-freedom wrist couplingan end effector body with an instrument shaft, in accordance with manyembodiments.

FIG. 7 is a perspective view of the two degree-of-freedom wrist of FIG.6, illustrating rotational degrees of freedom between an intermediatemember of the wrist and a support member of the wrist, and between theintermediate member and the end effector body, in accordance with manyembodiments.

FIG. 8a is a simplified diagrammatic illustration of a support-membercable-guiding surface and intermediate-member cable-guiding surfaces, inaccordance with many embodiments.

FIG. 8b is simplified diagrammatic illustration of intermediate-membercable-guiding surfaces, in accordance with many embodiments.

FIG. 9 is an end view of the support member of FIGS. 6 and 7,illustrating entrances to internal passages for guiding control cables,in accordance with many embodiments.

FIG. 10 is a perspective view of the two degree-of-freedom wrist ofFIGS. 6, and 7, illustrating the routing of actuation system componentsadjacent opposite sides of the two degree-of-freedom wrist and therouting of control cables through the two degree-of-freedom wrist, inaccordance with many embodiments.

FIG. 11a is a side view illustrating an angular orientation limitinghard contact between the intermediate member and the support member ofthe two degree-of-freedom wrist of FIGS. 6 and 7, in accordance withmany embodiments.

FIG. 11b is a side view illustrating an angular orientation limitinghard contact between the intermediate member of the twodegree-of-freedom wrist of FIGS. 6 and 7 and an end-effector body, inaccordance with many embodiments.

FIG. 12 is a simplified diagrammatic illustration of a surgicalassembly, in accordance with many embodiments.

FIG. 13a is a simplified diagrammatic illustration of a surgical toolhaving a second link coupled with a first link via a twodegree-of-freedom joint, the second link comprising curved portionattachment features that are coupled with linked tension members, theview direction being parallel with a second axis of the twodegree-of-freedom joint, in accordance with many embodiments.

FIG. 13b diagrammatically illustrates an attachment feature having acurved portion with a fixed center-of-curvature for its ordinarycenterline, in accordance with many embodiments.

FIG. 13c shows section A-A of FIG. 13 b.

FIG. 13d is a simplified diagrammatic illustration of the surgical toolof FIG. 13a , showing the second link rotated about the second axis, inaccordance with many embodiments.

FIG. 13e is a simplified diagrammatic illustration of the surgical toolof FIGS. 13a and 13d , the view direction being parallel with a firstaxis of the two degree-of-freedom joint, in accordance with manyembodiments.

FIG. 13f is a simplified diagrammatic illustration of the surgical toolof FIGS. 13a, 13d, and 13e , showing the second link rotated about thefirst axis, in accordance with many embodiments.

FIG. 13g is a perspective view of a surgical tool having a second linkcoupled with a first link via a two degree-of-freedom joint, the secondlink comprising curved portion attachment features that are coupled withlinked tension members, in accordance with many embodiments.

FIG. 13h is a side view of the surgical tool of FIG. 13g , showing a 60degree orientation of the second link about a first axis of the twodegree-of-freedom joint, in accordance with many embodiments.

FIG. 13i is a side view of the surgical tool of FIGS. 13g and 13h ,showing a 30 degree orientation of the second link about a second axisof the two degree-of-freedom joint, in accordance with many embodiments.

FIG. 14a is a simplified diagrammatic illustration of a surgical toolhaving a second link coupled with a first link via a twodegree-of-freedom joint, the second link comprising attachment lugs thatare coupled with linked tension members having curved portion ends, theview direction being parallel with a second axis of the twodegree-of-freedom joint, in accordance with many embodiments.

FIG. 14b is a simplified diagrammatic illustration of the surgical toolof FIG. 14a , showing the second link rotated about the second axis, inaccordance with many embodiments.

FIG. 14c is a simplified diagrammatic illustration of the surgical toolof FIGS. 14a and 14b , the view direction being parallel with a firstaxis of the two degree-of-freedom joint, in accordance with manyembodiments.

FIG. 14d is a simplified diagrammatic illustration of the surgical toolof FIGS. 14a, 14b, and 14c , showing the second link rotated about thefirst axis, in accordance with many embodiments.

FIG. 14e is a perspective view of a surgical tool having a second linkcoupled with a first link via a two degree-of-freedom joint, the secondlink comprising attachment lugs that are coupled with linked tensionmembers having curved portion ends, in accordance with many embodiments.

FIG. 15 is a simplified flowchart of a method for manufacturing asurgical tool, in accordance with many embodiments.

FIG. 16 is a simplified diagrammatic illustration of a surgicalassembly, in accordance with many embodiments.

FIG. 17 is a simplified diagrammatic illustration of a tool assemblyhaving a mechanism for transmitting torque through an angle, inaccordance with many embodiments.

FIG. 18 is a side view of a mechanism for transmitting torque through anangle in an inline configuration between a drive shaft and a drivenshaft, in accordance with many embodiments.

FIG. 19a is a cross-sectional view of the mechanism of FIG. 18,illustrating engagement between meshing spherical gear teeth of thedrive shaft and the driven shaft for the inline configuration, inaccordance with many embodiments.

FIG. 19b is a cross-sectional view of the mechanism of FIGS. 18 and 19a, illustrating engagement between the meshing spherical gear teeth ofthe drive shaft and the driven shaft for an angled configuration, inaccordance with many embodiments.

FIG. 19c illustrates an alternate shaft angle constraint configuration,in accordance with many embodiments.

FIG. 19d is a cross-sectional view of the mechanism of FIGS. 18, 19 a,and 19 b, illustrating the configuration of pin receiving transverseslots in the drive shaft and the driven shaft, in accordance with manyembodiments.

FIG. 20 is an assortment of perspective views of the drive and drivenshafts of FIGS. 18, 19 a, 19 b, and 19 d.

FIG. 21a is a side view of the mechanism of FIGS. 18, 19 a, 19 b, and 19c along a view direction normal to the coupling pins, in accordance withmany embodiments.

FIG. 21b is a side view of the mechanism of FIGS. 18, 19 a, 19 b, 19 c,and 21 a along a view direction parallel to the coupling pins, inaccordance with many embodiments.

FIG. 22a is a perspective view of drive and driven shafts havingmultiple rows of spherical gear teeth configured to provide shaft angleconstraint, in accordance with many embodiments.

FIG. 22b is a cross-sectional/perspective view of the drive and drivenshafts of FIG. 22a , illustrating gear teeth cross-sections and thespherical arrangement of the gear teeth.

FIG. 23a is a side view of a mechanism for transmitting torque throughan angle having a double cross pin design, in accordance with manyembodiments.

FIG. 23b is a side view of the mechanism of FIG. 23a without thecoupling element.

FIG. 23c is a cross-sectional view of the mechanism of FIGS. 23a and 23b.

FIG. 23d is a perspective view of the drive and driven shafts of FIGS.23a, 23b , and 23 c, showing a cross pin receiving bore in each of thedrive and driven shafts.

FIG. 23e is a perspective view of the drive and driven shafts of FIGS.23a, 23b, 23c, and 23d , illustrating the configuration of pin receivingtransverse slots in each of the drive and driven shafts.

FIG. 24a is a simplified diagrammatic illustration of a mechanism fortransmitting torque through an angle in which protrusions interactingwith slots transfer rotational motion between a drive shaft and acoupling member and between the coupling member and a driven shaft, inaccordance with many embodiments.

FIG. 24b is a view of the mechanism of FIG. 24a along a view directionparallel to the protrusions, in accordance with many embodiments.

FIG. 24c is a view of the mechanism of FIGS. 24a and 24b along a viewdirection normal to the protrusions, illustrating details of a two piececoupling member, in accordance with many embodiments.

FIG. 24d illustrates the mechanism of FIGS. 24a, 24b, and 24c in anangled configuration, in accordance with many embodiments.

FIGS. 25a and 25b are simplified diagrammatic illustrations of amechanism for transmitting torque through an angle in which modifiedU-joint coupling members transfer rotational motion between a driveshaft and a coupling member and between the coupling member and a drivenshaft, in accordance with many embodiments.

FIG. 26 illustrates a compact wrist design, in accordance with manyembodiments, having a two degree-of-freedom wrist that is articulated bylinked tension members, and double universal joints to transmit torquethrough an angle across the wrist.

DETAILED DESCRIPTION

In the following description, various embodiments of the presentinvention will be described. For purposes of explanation, specificconfigurations and details are set forth in order to provide a thoroughunderstanding of the embodiments. However, it will also be apparent toone skilled in the art that the present invention may be practicedwithout the specific details. Furthermore, well-known features may beomitted or simplified in order not to obscure the embodiment beingdescribed.

Surgical tools with a two degree-of-freedom wrist mechanism, and relatedmethods, are provided. In many embodiments, a two degree-of-freedomwrist includes an elongated intermediate wrist member that is pivotallycoupled with both a distal end of an instrument shaft and an endeffector body. The intermediate member can be pivotally coupled with theinstrument shaft to rotate about a first axis that is transverse to anelongate direction of the instrument shaft. The end effector body can bepivotally coupled with the intermediate member so as to rotate about asecond axis that is transverse to the first axis. Pivoting theintermediate member relative to the instrument shaft about the firstaxis, combined with pivoting an end effector body relative to theintermediate body about the second axis, can be used to reorient the endeffector body relative to the instrument shaft in two dimensions. Theability to reorient the end effector body in two dimensions can be usedto mimic the natural action of a surgeon's wrist, thereby providing adesirable amount of maneuverability for the end effector body.

In many embodiments, a two degree-of-freedom wrist is advantageouslyintegrated within a minimally invasive surgical tool. For example, theintermediate wrist member can have a length that is roughly equivalentto the diameter of an instrument shaft and a width that is significantlyless that the length, for example, a width that is less than one-thirdof the length; the width often being less than one-half the length, andin some cases the width being less than one-quarter the length. In manyembodiments, a centrally located pivot is used that provides forrotation of the intermediate member relative to the shaft or the endeffector body about an axis oriented transverse to the elongatedirection of the intermediate body, and two co-axial peripherallylocated pivots are used that provide for rotation of the intermediatemember relative to the shaft or the end effector body about an axisoriented parallel to the elongate direction of the intermediate body.The dimensions and the resulting motion of the intermediate memberleaves adjacent areas open for routing end effector articulation andactuation components. Advantageously, articulation components can berouted so as to be spaced apart from the first and second axes whilestill being within a cross section of the minimally invasive tool,thereby allowing the use of axial force articulation components, forexample, tensile force articulation components. Exemplary embodimentsmay employ both cables and rotational drive shafts that are offset fromthe intermediate wrist member, while an outer diameter of the tool(including the articulation components, end effector, and wrist jointsystem) will preferably be less than 1 inch, and often beingapproximately one-half inch. The intermediate wrist member can includerouting provisions with guidance features to route one or more controlcables through the intermediate wrist member. The wrist can beconfigured to transmit roll axis torque (e.g., 0.33 N m) across thewrist. The wrist can be configured with hard stops to limit the range ofmotion of the instrument to protect other components from damage due toangular over travel. The wrist can have a compact length, with pitchaxis to yaw axis distance adjustable down to zero offset.

In many embodiments, a two degree-of-freedom wrist includes internalpassages for guiding control cables. The internal passages can beconfigured to inhibit altering control cable tensions during pivotingabout the first and second axes.

Improved surgical and/or robotic wrist structures with wristarticulation by linked tension members are also provided. In manyembodiments, linked tension members are used to articulate a second linkthat is coupled with a first link via a two degree-of-freedom joint. Thelinked tension members can be coupled with the second link viaattachment features disposed on the second link. The geometries of thetwo degree-of-freedom joint, the linked tension members, and theattachment features can be selected so that opposed axial movement ofthe tension members angularly orients the second link relative to thefirst link so as to inhibit changes in tension in the tension members.In many embodiments, diagonally opposed tension members are paired andactuated by an actuation mechanism. For example, diagonally opposedtension members can be coupled with at least one control cable, and theat least one control cable can be actuated by a motor driven capstan.

The disclosed wrist articulation via linked tension members may beadvantageously employed in surgical tools having a second link coupledwith an elongate first link via a two degree-of-freedom joint. Thedisclosed wrist articulation may be particularly advantageous whenemployed in a minimally invasive surgical tool. Minimally invasivesurgical tools that are reliable and that have smooth operationalcharacteristics are desirable. By inhibiting changes in tension of thelinked tension members, detrimental control cable slack and/oroverstressing of tool components may be avoided. Actuating linkedtension members via a linear drive mechanism, for example, a motordriven capstan, may provide smooth operational characteristics. Thedisclosed wrist articulation also enables surgical tools with reducedlength distal of the first link, which improves access in a confinedbody space, angle of access to body structures, and visibility of bodystructures. The disclosed wrist articulation enables wrist articulationwithout interference with additional mechanisms passing through thewrist, for example, drive shafts. The disclosed wrist articulation mayalso provide increased longevity by avoiding the use of stranded cablesin the wrist. The disclosed wrist articulation can also be used toprovide 60 degrees of wrist articulation angle. The disclosed wristarticulation can also employ small diameter (e.g., hypodermic) tubing,which is advantageous for being readily attachable to flexible cablesdriven by motor driven capstans.

In many embodiments, a minimally invasive surgical tool having wristarticulation via linked tension members can include a second linkpivotally mounted to a first link via a two degree-of-freedom joint. Thejoint can have a first axis of rotation transverse to the first link anda second axis of rotation transverse to the first axis of rotation. Thesecond link can be coupled with four linked tension members so as toarticulate the second link relative to the first link. The four tensionmembers can be spaced apart from the two axes of the twodegree-of-freedom joint by locating one tension member in each quadrantdefined by the two axes while still being within the cross section ofthe minimally invasive tool. In exemplary embodiments, an outer diameterof the tool (including the linked tension members, other end effectoractuation components such as control cables and drive shafts, the endeffector, and the wrist joint system) will preferably be less than 1inch, and often approximately one-half inch.

Mechanisms for transmitting torque through an angle, minimally invasivesurgical tools comprising a mechanism for transmitting torque through anangle, and related methods are also provided. Such mechanisms have arelatively simple design, which may increase the reliability of themechanism by reducing the number of possible failure points. Forexample, in many embodiments, a mechanism for transmitting torquethrough an angle may have a reduced part count as compared to existingmechanisms.

The disclosed mechanisms may provide for a smooth transmission of torquethrough a range of angles. In many embodiments, a mechanism fortransmitting torque through an angle is operable to transmit torquethrough an angle exceeding 60 degrees. In many embodiments, therotational speed of an output shaft (e.g., a driven shaft) issubstantially equal to the rotational speed an input shaft (e.g., adrive shaft), even when the input and output shafts are non-parallel,which may provide for a smooth transmission of torque through an angleby avoiding the generation of vibration forces associated withnon-equivalent rotational speeds. The outer diameter of the mechanism(including the shafts, end effector, and joint system) will preferablybe less than 1 inch, often being less than ½ inch, and ideally being nomore than 8 mm (or in some cases, no more than 5 mm). To allow multipleshaft drive systems to fit within a single wrist, the drive shafts,driven shafts, and couplers of the mechanisms described herein willpreferably fit within a diameter of no more than 5 mm, and ideallywithin a diameter of no more than 3 mm. The torque transmitted acrossthe joint will often be more than 0.2 N m, and ideally being more than0.3 N m. To produce the desired work by the end effector in the desiredamount of time, the shafts and joint system will typically be rotatableat speeds of at least 100 rpm, and ideally being at least severalthousand rpm. The joints will preferably have a life of at least severalminutes of operation when driven at maximum torque and wrist angle, andideally of at least several hours. The exemplary drive shaft to drivenshaft joint assembly, excluding the shafts themselves, includes fewerthan 10 separately fabricated and/or machined parts, and in manyembodiments only 3 separately fabricated and/or machined parts.

Available materials can be used to fabricate components of the disclosedmechanisms. In many embodiments, the drive shaft, driven shaft, andcoupler can be fabricated from, for example, 465 stainless steel,condition H950. The drive and driven shaft ends can be integral to theshafts. The cross pins can be fabricated from, for example, Nitronic 60stainless steel, 30 percent cold worked.

The disclosed mechanisms may be particularly beneficial when used aspart of a minimally invasive surgical tool. As discussed above,minimally invasive surgical tools are typically introduced into apatient through a cannula sleeve, which constrains the diameter of thetool. The relatively simple design of the disclosed mechanisms can besized for use within a minimally invasive surgical tool. The relativelysimple design also may reduce possible failure points, a reduction whichmay increase the reliability of a minimally invasive surgical tool. Theability to configure the disclosed mechanisms to transmit torque throughan angle exceeding 60 degrees enables the use of a relatively largeamount of articulation between an end effector and an instrument shaftof a minimally invasive surgical tool. The ability of the disclosedmechanisms to smoothly transmit torque through an angle through the useof equivalent rotational speeds may also be beneficial by avoiding harmto the patient and/or the surgical tool that may result from thegeneration of vibration movements and/or forces.

Referring now to the drawings, in which like reference numeralsrepresent like parts throughout the several views, in accordance withmany embodiments, FIG. 1 through FIG. 5b illustrate aspects of minimallyinvasive robotic surgery systems, FIG. 6 through FIG. 12 illustrateaspects of two degree-of-freedom wrists, FIG. 13a through FIG. 16illustrate aspects of wrist articulation by linked tension members, andFIG. 17 through FIG. 25b illustrate aspects of mechanisms fortransmitting torque through an angle. As can be appreciated, theforegoing features can be utilized individually, or in any combination.For example, FIGS. 10, 13 g, 13 h, 13 i, and 26 illustrates a compactwrist design having a two degree-of-freedom wrist that is articulated bylinked tension members as disclosed herein, as well as the use of doubleuniversal joints to transmit torques through an angle across the twodegree-of-freedom wrist.

Minimally Invasive Robotic Surgery

FIG. 1 is a plan view illustration of a Minimally Invasive RoboticSurgical (MIRS) system 10, typically used for performing a minimallyinvasive diagnostic or surgical procedure on a Patient 12 who is lyingdown on an Operating table 14. The system can include a Surgeon'sConsole 16 for use by a Surgeon 18 during the procedure. One or moreAssistants 20 may also participate in the procedure. The MIRS system 10can further include a Patient-Side Cart 22 (surgical robot), and anElectronics Cart 24. The Patient Side Cart 22 can manipulate at leastone removably coupled tool assembly 26 (hereinafter simply referred toas a “tool”) through a minimally invasive incision in the body of thePatient 12 while the Surgeon 18 views the surgical site through theConsole 16. An image of the surgical site can be obtained by anendoscope 28, such as a stereoscopic endoscope, which can be manipulatedby the Patient-Side Cart 22 so as to orient the endoscope 28. TheElectronics Cart 24 can be used to process the images of the surgicalsite for subsequent display to the Surgeon 18 through the Surgeon'sConsole 16. The number of surgical tools 26 used at one time willgenerally depend on the diagnostic or surgical procedure and the spaceconstraints within the operating room among other factors. If it isnecessary to change one or more of the tools 26 being used during aprocedure, an Assistant 20 may remove the tool 26 from the Patient-SideCart 22, and replace it with another tool 26 from a tray 30 in theoperating room.

FIG. 2 is a perspective view of the Surgeon's Console 16. The Surgeon'sConsole 16 includes a left eye display 32 and a right eye display 34 forpresenting the Surgeon 18 with a coordinated stereo view of the surgicalsite that enables depth perception. The Console 16 further includes oneor more input control devices 36, which in turn cause the Patient-SideCart 22 (shown in FIG. 1) to manipulate one or more tools. The inputcontrol devices 36 will provide the same degrees of freedom as theirassociated tools 26 (shown in FIG. 1) so as to provide the Surgeon withtelepresence, or the perception that the input control devices 36 areintegral with the tools 26 so that the Surgeon has a strong sense ofdirectly controlling the tools 26. To this end, position, force, andtactile feedback sensors (not shown) may be employed to transmitposition, force, and tactile sensations from the tools 26 back to theSurgeon's hands through the input control devices 36.

The Surgeon's Console 16 is usually located in the same room as thepatient so that the Surgeon may directly monitor the procedure, bephysically present if necessary, and speak to an Assistant directlyrather than over the telephone or other communication medium. However,the Surgeon can be located in a different room, a completely differentbuilding, or other remote location from the Patient allowing for remotesurgical procedures (i.e., operating from outside the sterile field).

FIG. 3 is a perspective view of the Electronics Cart 24. The ElectronicsCart 24 can be coupled with the endoscope 28 and can include a processorto process captured images for subsequent display, such as to a Surgeonon the Surgeon's Console, or on any other suitable display locatedlocally and/or remotely. For example, where a stereoscopic endoscope isused, the Electronics Cart 24 can process the captured images so as topresent the Surgeon with coordinated stereo images of the surgical site.Such coordination can include alignment between the opposing images andcan include adjusting the stereo working distance of the stereoscopicendoscope. As another example, image processing can include the use ofpreviously determined camera calibration parameters so as to compensatefor imaging errors of the image-capture device, such as opticalaberrations.

FIG. 4 diagrammatically illustrates a robotic surgery system 50 (such asMIRS system 10 of FIG. 1). As discussed above, a Surgeon's Console 52(such as Surgeon's Console 16 in FIG. 1) can be used by a Surgeon tocontrol a Patient-Side Cart (Surgical Robot) 54 (such as Patent-SideCart 22 in FIG. 1) during a minimally invasive procedure. ThePatient-Side Cart 54 can use an imaging device, such as a stereoscopicendoscope, to capture images of the procedure site and output thecaptured images to an Electronics Cart 56 (such as the Electronics Cart24 in FIG. 1). As discussed above, the Electronics Cart 56 can processthe captured images in a variety of ways prior to any subsequentdisplay. For example, the Electronics Cart 56 can overlay the capturedimages with a virtual control interface prior to displaying the combinedimages to the Surgeon via the Surgeon's Console 52. The Patient-SideCart 54 can output the captured images for processing outside theElectronics Cart 56. For example, the Patient-Side Cart 54 can outputthe captured images to a processor 58, which can be used to process thecaptured images. The images can also be processed by a combination theElectronics Cart 56 and the processor 58, which can be coupled togetherso as to process the captured images jointly, sequentially, and/orcombinations thereof. One or more separate displays 60 can also becoupled with the processor 58 and/or the Electronics Cart 56 for localand/or remote display of images, such as images of the procedure site,or any other related images.

FIGS. 5a and 5b show a Patient-Side Cart 22 and a surgical tool 62,respectively. The surgical tool 62 is an example of the surgical tools26. The Patient-Side Cart 22 shown provides for the manipulation ofthree surgical tools 26 and an imaging device 28, such as a stereoscopicendoscope used for the capture of images of the site of the procedure.Manipulation is provided by robotic mechanisms having a number ofrobotic joints. The imaging device 28 and the surgical tools 26 can bepositioned and manipulated through incisions in the patient so that akinematic remote center is maintained at the incision so as to minimizethe size of the incision. Images of the surgical site can include imagesof the distal ends of the surgical tools 26 when they are positionedwithin the field-of-view of the imaging device 28.

Two Degree-of-Freedom Wrist

FIG. 6 is a perspective view of a two degree-of-freedom wrist 70coupling an end effector body 72 with an instrument shaft 74, inaccordance with many embodiments. The wrist 70 includes a support member76, a first hinge point 78, an intermediate member 80, a second hingepoint 82, and a third hinge point 84. The support member 76 is fixedlymounted to the instrument shaft 74 via four attachment features 86(e.g., mechanical fasteners) so as to be positioned within a bore of theinstrument shaft 74 as illustrated. The intermediate member 80 ispivotally coupled with the support member 76 for rotation about a firstaxis 88 via the centrally-located first hinge point 78. The end effectorbody 72 is pivotally coupled with the intermediate member 80 forrotation about a second axis 90 via the peripherally-located secondhinge point 82 and the peripherally-located third hinge point 84. Thesecond hinge point 82 and the third hinge point 84 are coaxial andaligned with the second axis 90. The second axis 90 pivots with theintermediate member about the first axis 88.

The first axis 88 and the second axis 90 can be positioned to provide acompact two degree-of-freedom wrist with desired kinematics and/orspatial characteristics. For example, the first axis 88 and the secondaxis 90 can be coplanar, and thereby provide a compact wrist member withball joint like kinematics. In many embodiments, the first axis 88 andthe second axis 90 are separated by a desired distance along an elongatedirection of the instrument shaft 74. Such a separation can be used toapproximate and/or match the kinematics of the wrist mechanism to thekinematics of actuation system components used to orient the endeffector body 72 relative to the instrument shaft 74 via the twodegree-of-freedom wrist. In many embodiments, the first axis 88 and thesecond axis 90 are separated by a desired distance along the elongatedirection of the instrument shaft 74 so as to provide a twodegree-of-freedom wrist with a desired combination of compactness andkinematics that approximately match the kinematics of the actuationsystem components used to orient the end effector body 72 relative tothe instrument shaft 74. For example, if a 4 mm separation between thefirst axis 88 and the second axis 90 would match the kinematics of theactuation system orientation components used, the two degree-of-freedomwrist can be configured with a smaller separation (e.g., 2 mm) so as toprovide a more compact wrist. In many embodiments, such a separationdistance compromise can be employed without inducing any significantdetrimental operating characteristics from not exactly matching thekinematics of the actuation system orientation components used. Thefirst axis 88 and the second axis 90 can be positioned to provide acompact two degree-of-freedom wrist with desired spatialcharacteristics. For example, the first axis 88 and the second axis 90can be separated to provide additional space for actuation systemcomponents and related attachment features.

The support member 76 provides a transitional fitting between theinstrument shaft 74 and the first hinge point 78. The support member 76includes a rectangular main portion 92 and a cantilevered distal portion100. The rectangular main portion 92 has a thickness that is less thanthe inside diameter of the instrument shaft bore, which leaves twoadjacent regions of the bore open for the routing of articulation and/oractuation components (not shown). The support-member main portion 92includes two internal passages 94, which can be used to guide endeffector control cables routed within the instrument-shaft bore. Theinternal passages 94 are routed between a proximal end 96 of the mainportion 92 and a distal end 98 of the main portion 92 and are generallyaligned with the elongate direction of the instrument shaft 74. As willbe discussed further below, in many embodiments, the internal passages94 are configured to work in conjunction with cable guide surfaces ofthe intermediate member to inhibit altering control cable tensionsduring pivoting about the first and second axes by maintaining constantcontrol cable path lengths. The cantilevered distal portion 100 has anattachment lug that receives a single pivot shaft of the first hingepoint 78. The use of a single pivot shaft is merely exemplary, and otherpivot joint components can be used in place of the first hinge point 78,for example, two pivot pins aligned on the same axis can be used. Thesupport member 76 is configured to place the first hinge point 78 (andtherefore the first axis 88) at a desired location relative to theinstrument shaft 74 and the end effector body 72, for example, toprovide clearance between the end effector body 72 and the instrumentshaft 74 necessary for a desired range of reorientation of the endeffector body 72 relative to the instrument shaft 74.

The intermediate member 80 provides a transitional fitting between thefirst hinge point 78, the second hinge point 82, and the third hingepoint 84. The intermediate member 80 includes an elongate rectangularmain portion that has a thickness that is less than the inside diameterof the instrument shaft bore (e.g., similar to the thickness of mainportion 92), which leaves two adjacent regions open for the routing ofarticulation and/or actuation components (not shown). The intermediatemember 80 includes a central slot 102 configured to receive theattachment lug of the support-member distal portion 100. The centralslot 102 is configured to accommodate the attachment lug of the distalportion 100 throughout a range of rotation of the intermediate member 80about the first axis 88. The central slot 102 can also be configured toaccommodate end effector control cables (not shown) that are routedthrough the support-member internal passages 94. The central slot 102can also include surfaces configured to guide end effector controlcables. As will be discussed further below, in many embodiments, thecentral-slot cable-guiding surfaces are configured to inhibit alteringcontrol cable tensions during pivoting about the first and second axesby maintaining substantially constant control cable path lengths. Inmany embodiments, the central-slot cable guiding surfaces work inconjunction with the internal passages 94 to maintain constant controlcable path lengths during pivoting about the first and second axes. Thecentral slot 102 also provides opposing attachment flanges that receivethe single pivot shaft of the first hinge point 78. The second hingepoint 82 includes a pivot shaft cantilevered from a first end of theintermediate member 80. The third hinge point 84 includes a pivot shaftcantilevered from an opposing second end of the intermediate member 80.The use of cantilevered pivot shafts is merely exemplary, and othersuitable pivot joints can be used. In many embodiments, the positionsand orientations of the second and third hinge points 82, 84 (and hencethe position and orientation of the second axis 90) are selected so asto provide a desired position and orientation of the second axis 90relative to the first axis 88. For example, in many embodiments, thefirst and second axes are non-coplanar. In many embodiments, the firstand second axes are coplanar. In many embodiments, the position and/ororientation of the second axis 90 relative to the first axis 88 isselected to provide desired kinematics for the movement of the endeffector body 72 relative to the instrument shaft 74.

FIG. 7 is a perspective view of the two degree-of-freedom wrist 70 ofFIG. 6, illustrating the rotational degree-of-freedom between theintermediate member 80 and the support member 76 about the first axis88, and the rotational degree-of-freedom between the end effector body(not shown) and the intermediate member 80 about the second axis 90, inaccordance with many embodiments. The support member 76 is mounted tothe instrument shaft 74 so as to position the first hinge point 78 as adesired location distal from the distal end of the instrument shaft 74,for example, to provide clearance between the end effector body and theinstrument shaft so as to provide space for articulation of the endeffector body. The intermediate-member central slot 102 is open to theside of the intermediate member 80 adjacent to the end effector body soas to accommodate routing of end effector control cables (not shown).From the view direction of FIG. 7, one internal passage 94 of thesupport member 76 is visible and the other internal passage 94 is hiddenfrom view. In many embodiments, one control cable is routed through eachof the two internal passages 94. Each of these two control cables isfurther routed through the intermediate-member central slot 102, one oneach side of the first axis 88.

FIG. 8a is a diagrammatic cross-sectional view of the wrist 70 takenthrough the second axis 90 and normal to the first axis 88, and whichshows illustrative support and intermediate member cable guidingsurfaces. The support member distal end 100 includes a first pulleysurface 104 with a curved arc shape such that the centerline of thecurved arc shape is aligned with the first axis 88. Inner surfaces ofthe intermediate member slot 102 define a second pulley surface 106 anda third pulley surface 108 with curved arc shapes such that centerlinesof the curved arc shapes (second pulley centerline 110 and third pulleycenterline 112) are offset from and parallel to the first axis 88.Although the pulley surfaces illustrated have constant curvatures, thisis merely exemplary and other suitable surfaces can be used. The firstpulley surface 104, second pulley surface 106, and third pulley surface108 provide smooth cable-guiding surfaces that can guide control cablesfor rotations of the intermediate body 80 about the first axis 88 (andtherefore for rotations of the end effector body about the first axis88). In many embodiments, the first pulley surface 104, second pulleysurface 106, and third pulley surface 108 inhibit altering control cabletensions during pivoting about the first axis by maintaining constantcontrol cable path lengths. In many embodiments, the first pulleysurface 104, second pulley surface 106, and third pulley surface 108work in conjunction with the internal passages 94 to maintain constantcontrol cable path lengths during pivoting about the first axis.

FIG. 8b is a simplified diagrammatic illustration of additionalintermediate-member cable-guiding surfaces, in accordance with manyembodiments. FIG. 8b illustrates cross section AA of FIG. 8a . Innersurfaces of the intermediate-member slot 102 further define a fourthpulley surface 114 and a fifth pulley surface 116 with curved arc shapeswith centerlines of the curved arc shapes (fourth pulley centerline 118and fifth pulley centerline 120) that are offset from and parallel tothe second axis 90. Although the pulley surfaces illustrated haveconstant curvatures, this is merely exemplary and other suitablesurfaces can be used. The fourth pulley surface 114 and the fifth pulleysurface 116 provide smooth cable-guiding surfaces that can guide controlcables for rotations of the end effector body relative to theintermediate body 80 about the second axis 90. In many embodiments, thefourth pulley surface 114 and the fifth pulley surface 116 inhibitaltering control cable tensions during pivoting about the second axis bymaintaining substantially constant control cable path lengths. In manyembodiments, the fourth pulley surface 114 and the fifth pulley surface116 work in conjunction with the internal passages 94 to maintainconstant control cable path lengths during pivoting about the secondaxis.

FIG. 9 is a proximal end view of the support member 76 of FIGS. 6 and 7,illustrating entrances to the internal passages 94 for guiding controlcables of an actuation system, in accordance with many embodiments. Thesupport member internal passages 94 can be used to constrain thecross-sectional position of the control cables at the distal end of theinstrument shaft.

FIG. 10 is a perspective view of the two degree-of-freedom wrist 70 ofFIGS. 6, 7, and 8, showing an illustrative routing of actuation systemcomponents along two sides of the two degree-of-freedom wrist 70 androuting of control cables 122,124 through the two degree-of-freedomwrist 70, in accordance with many embodiments. The generally planarconfiguration of the two degree-of-freedom wrist, and its centrallocation within the shaft that supports it, leaves adjacent areas openfor the routing of such actuation system components. In the illustratedembodiment, these actuation systems components include a first driveshaft assembly 126 routed above the wrist, a second drive shaft assembly128 routed below the wrist, end effector articulation pull rods 130,132, 134, and 136 routed above and below the wrist, and control cables122,124 routed through the wrist via the internal passages of thesupport member and the intermediate-member slot 102 as discussed above.

The two degree-of-freedom wrist 70 includes features that provideangular orientation limiting hard contact for both rotation around thefirst axis 88 (via the first joint 78) and rotation around the secondaxis 90 (via the second joint 82 and the third joint 84). Such angularorientation limiting hard contact serves to protect wrist traversingcomponents from damage due to angular over travel. FIG. 11a illustratesan angular orientation limiting hard contact between the intermediatemember 80 and the support member 76 of the two degree-of-freedom wrist70 for rotation about the first axis 88 (via the first joint 78). Asimilar angular orientation limiting hard contact occurs between theintermediate member 80 and the support member 76 when the intermediatemember 80 is rotated in the opposite direction about the first joint 78.FIG. 11b illustrates an angular orientation limiting hard contactbetween the intermediate member 80 of the two degree-of-freedom wrist 70and the end-effector body 72 for rotation about the second axis 90 (viathe second joint 82 and the third joint 84). A similar angularorientation limiting hard contact occurs between the intermediate member80 and the end-effector body 72 when the end-effector body 72 is rotatedin the opposite direction about the second axis 90.

FIG. 12 is a simplified diagrammatic illustration of a tool assembly 140having the two degree-of-freedom wrist 70, in accordance with manyembodiments. The tool assembly 140 includes a proximal actuationassembly 142, a main shaft 144, an articulated end effector base of anend effector 146, and the two degree-of-freedom wrist 70. In manyembodiments, the proximal actuation assembly 142 is operatively coupledwith the end effector base so as to selectively reorient the endeffector base relative to the main shaft 144 in two dimensions, and isoperatively coupled with the end effector 146 so as to articulate one ormore end effector features relative to the end effector base. A varietyof actuation components can be used to couple the actuation assembly 142with the end effector 146, for example, control cables, cable/hypotubecombinations, drive shafts, pull rods, and push rods. In manyembodiments, the actuation components are routed between the actuationassembly 142 and the end effector 146 through a bore of the main shaft144.

The tool assembly 140 can be configured for use in a variety ofapplications, for example, as a hand-held device with manual and/orautomated actuation used in the proximal actuation mechanism 142. Assuch, the tool assembly 140 can have applications beyond minimallyinvasive robotic surgery, for example, non-robotic minimally invasivesurgery, non-minimally invasive robotic surgery, non-roboticnon-minimally invasive surgery, as well as other applications where theuse of a two degree-of-freedom wrist would be beneficial.

Wrist Articulation By Linked Tension Members

FIG. 13a is a simplified diagrammatic illustration of a surgical tool170 with wrist articulation by linked tension members, in accordancewith many embodiments. The surgical tool 170 includes a second link 172that is pivotally coupled with a first link 174 via a twodegree-of-freedom joint. The joint provides for rotational motionbetween the second link 172 and the first link 174 about a first axis176 and a second axis 178. The first axis 176 is fixed relative to thefirst link 174, and the second axis 178 is fixed relative to the secondlink 172. Four attachment features 180, 182, 184, 186 are disposed onthe second link 172. Each of the attachment features 180, 182, 184, 186is coupled with a tension member 188, 190, 192, 194, respectively. Thetension members 188, 190, 192, 194 are routed through a bore of thefirst link 174 and are coupled with an actuation mechanism 196 viacontrol cables 198, 200, 202, 204. In many embodiments, the tensionmembers 188, 190, 192, 194 are configured to minimize stretching underoperational loading and to reduce cost (e.g., 17 inches long, 0.04-inchoutside diameter, 0.02-inch inside diameter; 15.2 inches long, 0.06-inchoutside diameter, 0.02-inch inside diameter). In many embodiments, theattachment features 180, 182, 184, 186, the tension members 188, 190,192, 194, the first axis 176, and the second axis 178 are configured sothat opposed axial movement of the tension members angularly orients thesecond link 172 relative to the first link 174 so as to inhibit changesin tension in the tension members. In the embodiment illustrated, theactuation mechanism 196 includes a first motor driven capstan 206 and asecond motor driven capstan 208. A first diagonally opposed pair ofcontrol cables (e.g., control cables 198, 202) are wrapped around thefirst motor driven capstan 206 so that a clockwise rotation of the firstmotor driven capstan 206 will retract control cable 202 and extendcontrol cable 198 by an equal amount, and a counter-clockwise rotationof the first motor driven capstan 206 will retract control cable 198 andextend control cable 202 by an equal amount. Likewise, a seconddiagonally opposed pair of control cables (e.g., control cables 200,204) are wrapped around the second motor driven capstan 208 so that aclockwise rotation of the second motor driven capstan 208 will retractcontrol cable 200 and extend control cable 204 by an equal amount, and acounter-clockwise rotation of the second motor driven capstan 208 willretract control cable 204 and extend control cable 200 by an equalamount.

FIGS. 13b and 13c diagrammatically illustrates one of the attachmentfeatures 180, 182, 184, 186. The attachment features 180, 182, 184, 186have a curved portion 210 with a fixed center-of-curvature 212 for itscurved ordinary centerline 214, and a first radius of curvature 216about its curved ordinary centerline 214. Each of the fixedcenter-of-curvatures can be located on a two-dimensional planecontaining the second axis 178. The curved ordinary centerlines can lieon two-dimensional planes oriented normal to the second axis 178. Thefour curved ordinary centerlines can be tangent to a two-dimensionalplane containing the first axis 176. Each of the tension members 188,190, 192, 194 has an attachment lug 218, 220, 222, 224 with hole axisoriented normal to the tension member length. The attachment lug holesare sized to slidingly receive a corresponding attachment feature curvedportion. The attachment lugs are configured to rotate about a curvedportion and/or slide along a curved portion during articulation of thesecond link 172 relative to the first link 174.

When the second link 172 rotates about the second axis 178, theattachment lugs 218, 220, 222, 224 slide along a corresponding curvedportion of the attachment features 180, 182, 184, 186. FIG. 13d is asimplified diagrammatic illustration of the surgical tool 170 of FIG.13a , showing the second link 172 rotated about the second axis 178, inaccordance with many embodiments. Each of the attachment lugs 218, 220,222, 224 slides along a corresponding attachment feature curved portionso that each of the tension members is aligned with the fixedcenter-of-curvature for its corresponding attachment feature curvedportion section. As a result, the upper tension members 190, 194 extendby the same amount that the lower tension members 188, 192 retract (ascompared to the neutral second link orientation depicted in FIG. 13a ).With such a balanced extension/retraction of the tension members, one ormore pairs of the tension members can be linked and actuated by a commonactuation mechanism. For example, diagonally opposed tension members canbe coupled with at least one control cable, and the at least one controlcable can be actuated by a motor driven capstan. Rotation of the motordriven capstan (e.g., servo controlled) can be used to simultaneously(and equally) extend a section of control cable coupled with a first ofthe pair of tension members and retract a section of control cablecoupled with a second of the pair of tension members. Such simultaneousand equal extension/retraction of control cable can inhibit alteringtension in the linked tension members, which may help to avoid anydetrimental control cable slack and/or overstressing of tool components.

FIG. 13e illustrates the surgical tool 170 of FIGS. 13a and 13d from aview direction parallel with the first axis 176 of the twodegree-of-freedom joint, in accordance with many embodiments. Asdiscussed above, the attachment features 180, 182, 184, 186 includecurved portion sections having ordinary centerlines and fixedcenters-of-curvature. Each of the ordinary centerlines is tangent to aplane containing the first axis 176 of the two degree-of-freedom joint.Each of the fixed centers-of-curvature lies in a plane containing thesecond axis 178 of the two degree-of-freedom joint.

When the second link 172 rotates about the first axis 176, theattachment lugs 218, 220, 222, 224 rotate about a correspondingattachment feature curved portion ordinary centerline. FIG. 13f is asimplified diagrammatic illustration of the surgical tool 170 of FIGS.13a, 13d, and 13e , showing the second link 172 rotated about the firstaxis 176, in accordance with many embodiments. Each of the attachmentlugs 218, 220, 222, 224 rotates about a corresponding curved portionordinary centerline of the attachment features 180, 182, 184, 186 sothat each of the tension members is aligned with the correspondingcenterline. As a result, the upper tension members 188, 190 extend bythe same amount that the lower tension members 192, 194 retract (ascompared to the neutral second link orientation depicted in FIG. 13e ).As discussed above, with such a balanced extension/retraction of thetension members, one or more pairs of the tension members can be linkedand actuated by a common actuation mechanism. For example, a first pairof the four tension members comprising two diagonally opposed tensionmembers 188, 194 can be actuated by a first motor driven capstan, and asecond pair of the four tension members comprising the remaining twodiagonally opposed tension members 190, 192 can be actuated by a secondmotor driven capstan. The first and second motor driven capstans can beused to articulate the second link 172 relative to the first link 174within the range of orientations provided for by the twodegree-of-freedom joint.

FIG. 13g is a perspective partial view of a surgical tool 230 having asecond link 232 coupled with a first link 234 via a twodegree-of-freedom joint, in accordance with many embodiments. The twodegree-of freedom joint illustrated includes an intermediate member 236that is pivotally coupled to rotate about a first axis relative to asupport member 238. The second link 232 is pivotally coupled with theintermediate member 236 so as to rotate about a second axis relative tothe intermediate member 236. The second link 232 comprises fourattachment features 240, 242, 244, (246 hidden from view), whichcomprise curved portion sections. Four tension members 248, 250, 252,(254 hidden from view) are coupled with the four attachment features240, 242, 244, 246.

The surgical tool 230 illustrated is configured similar to the surgicaltool 170 discussed above and illustrated in FIGS. 13a, 13d, 13e, and 13fAccordingly, the above discussion regarding the surgical tool 170applies to the surgical tool 230 illustrated in FIG. 13g , which furtherillustrates wrist articulation via linked tension members. FIG. 13h is aside view of the surgical tool 230 of FIG. 13g , showing a 60 degreeorientation of the second link 232 about the first axis of the twodegree-of-freedom joint, in accordance with many embodiments. From thealigned orientation illustrated in FIG. 13g to the orientationillustrated in FIG. 13h , the tension member attachment lugs havepivoted around the ordinary centerlines of the curved portion sectionsof the attachment features, thereby maintaining the alignment betweenthe tension members and the ordinary centerlines of the curved portionsections. FIG. 13i is a side view of the surgical tool 230 of FIG. 13g ,showing a 30 degree orientation of the second link about a second axisof the two degree-of-freedom joint, in accordance with many embodiments.From the aligned orientation illustrated in FIG. 13g to the orientationillustrated in FIG. 13i , the tension member attachment lugs have slidalong the curved portion sections of the attachment features, therebymaintaining the alignment between the tension members and the fixedcenter-of-curvatures for the curved portion sections.

FIG. 14a is a simplified diagrammatic illustration of a surgical tool260 with wrist articulation by linked tension members, in accordancewith many embodiments. A surgical tool 260 includes a second link 262that is pivotally coupled with a first link 264 via a twodegree-of-freedom joint. The joint provides for rotational motionbetween the second link 262 and the first link 264 about a first axis266 and a second axis 268. The first axis 266 is fixed relative to thefirst link 264, and the second axis 268 is fixed relative to the secondlink 262. Four attachment features 270, 272, 274, 276 are disposed onthe second link 262. Each of the attachment features 270, 272, 274, 276is coupled with a tension member 278, 280, 282, 284, respectively. Thetension members 278, 280, 282, 284 are routed through a bore of thefirst link 264 and are coupled with an actuation mechanism (not shown;e.g., an actuation mechanism associated with actuating a teleoperatedsurgical instrument in a telerobotic surgical system as describedabove). In many embodiments, the attachment features 270, 272, 274, 276,the tension members 278, 280, 282, 284, the first axis 266, and thesecond axis 268 are configured so that opposed axial movement of thetension members angularly orients the second link 262 relative to thefirst link 264 so as to inhibit changes in tension in the tensionmembers.

Each of the attachment features 270, 272, 274, 276 includes anattachment lug with a hole axis oriented parallel to the second axis268. Each of the tension members 278, 280, 282, 284 can comprise asection of curved portion having a first radius of curvature about itsordinary centerline and a fixed center-of-curvature for its curvedcenterline. The curved ordinary centerlines can lie on two-dimensionalplanes oriented normal to the first axis 266. The attachment feature lugholes are sized to slidingly receive a tension member curved portion.The attachment feature lugs are configured to rotate about a tensionmember curved portion and/or slide along a tension member curved portionduring articulation of the second link 262 relative to the first link264.

When the second link 262 rotates about the second axis 268, each of thecurved portions of the tension members slides against a correspondingattachment feature lug. FIG. 14b is a simplified diagrammaticillustration of the surgical tool 260 of FIG. 14a , showing the secondlink 262 rotated about the first axis 266, in accordance with manyembodiments. Each of the curved portions of the tension members slidesagainst a corresponding attachment feature lug. As a result, the uppertension members 280, 284 extend by the same amount that the lowertension members 278, 282 retract (as compared to the neutral second linkorientation depicted in FIG. 14a ). This provides a balancedextension/retraction of the tension members, similar to the surgicaltool 170 discussed above. Accordingly, additional aspects and benefitsof such a balanced extension/retraction of the tension members discussedabove with regard to the surgical tool 170 applies to the surgical tool260, and they will not be repeated here.

FIG. 14c illustrates the surgical tool 260 of FIGS. 14a and 14b from aview direction parallel with the second axis 268 of the twodegree-of-freedom joint, in accordance with many embodiments. Asdiscussed above, each of the attachment features 270, 272, 274, 276include an attachment lug with a hole axis oriented parallel to thesecond axis 268. Each of the tension members includes a curved portionsection having an ordinary centerline and a fixed center-of-curvature.

When the second link 262 rotates about the second axis 268, the tensionmember curved portions pivot within the attachment feature lugs. FIG.14d is a simplified diagrammatic illustration of the surgical tool 260of FIGS. 14a, 14b, and 14c , showing the second link 262 rotated aboutthe second axis 268, in accordance with many embodiments. Each of thetension member curved portions pivots within a corresponding attachmentfeature lug hole so that each of the tension members remains alignedwith the corresponding attachment feature lug hole. As a result, theupper tension members 278, 280 extend by the same amount that the lowertension members 282, 284 retract (as compared to the neutral second linkorientation depicted in FIG. 14c ). As discussed above, with such abalanced extension/retraction of the tension members, one or more pairsof the tension members can be linked and actuated by a common actuationmechanism. Accordingly, additional aspects and benefits of such abalanced extension/retraction of the tension members discussed abovewith regard to the surgical tool 170 applies to the surgical tool 260,and will not be repeated here.

FIG. 14e is a partial perspective view of a surgical tool 290 having asecond link 292 coupled with a first link (not shown) via a twodegree-of-freedom joint, in accordance with many embodiments. The twodegree-of freedom joint illustrated includes an intermediate member 294that is pivotally coupled to rotate about a first axis relative to asupport member 296. The second link 292 is pivotally coupled to rotateabout a second axis relative to the intermediate member 294. The secondlink 292 comprises four attachment features 298, 300, 302, (304 hiddenfrom view), each of which comprise an attachment lug. Four tensionmembers 306, 308, 310, 312 are coupled with the four attachment features298, 300, 302, 304. Each of the four tension members 306, 308, 310, 312comprises a curved portion section slidingly received by a correspondingattachment feature lug. The surgical tool 290 illustrated is configuredsimilar to the surgical tool 260 discussed above and illustrated inFIGS. 14a, 14b, 14c, and 14d . Accordingly, the above discussionregarding the surgical tool 260 applies to the surgical tool 290illustrated in FIG. 14e , which further illustrates wrist articulationvia linked tension members.

FIG. 15 is a simplified flowchart of a method 320 for manufacturing asurgical tool, in accordance with many embodiments. In act 322, a secondlink is coupled with a first link to rotate about first and second axes.For example, a two degree-of-freedom joint mechanism can be used tocouple the second link to the first link. The two degree-of-freedomjoint can include an intermediate member that is pivotally coupled withthe second link to rotate relative to the first link about a first axis.The second link can be pivotally coupled with the intermediate member torotate relative to the intermediate member about a second axis. Thefirst link can have a distal end, a proximal end, and a first link axisdefined there between.

The first link can have an axial bore. The first and second axes can benonparallel to the first link axis. The first axis can be nonparallel tothe second axis. The second link can comprise four attachment features.Each of the attachment features can be offset from the first and secondaxes when viewed along the first link axis. One of the attachmentfeatures can be disposed in each quadrant defined by the first andsecond axes when viewed along the first link axes.

In act 324, a tension member is coupled with each of the second linkattachment features. Each of the tension members can extend distallyfrom within the bore of the first link to one of the attachment featuresof the second link so that axial movement of the tension membersangularly orients the second link relative to the first link about theaxes. Interface surfaces between the tension members and the attachmentfeatures can vary a position of the tension members relative to thesecond link in correlation with the angular orientation of the secondlink relative to the first link so as to inhibit changes in tension ofthe tension members.

In act 326, each of the tension members is coupled with an actuationmechanism operable to control the angular orientation of the second linkrelative to the first link in two dimensions by actuating the tensionmembers. For example, a first of the four tension members can be coupledwith a first control cable, and a second of the tension members can becoupled with a second control cable. The first and the second tensionmembers can be diagonally opposed tension members. The first and secondcontrol cables can be coupled with a first capstan of the actuationmechanism. A third of the four tension members can be coupled with athird control cable, and a fourth of the tension members can be coupledwith a fourth control cable. The third and the fourth tension memberscan be diagonally opposed tension members. The third and fourth controlcables can be coupled with a second capstan of the actuation mechanism.

FIG. 16 is a simplified diagrammatic illustration of a tool assembly 330having a wrist articulated by linked tension members, in accordance withmany embodiments. The tool assembly 330 includes a proximal actuationassembly 332, a main shaft 334, an articulated end effector base of anend effector 336, and a two degree-of-freedom wrist 338. In manyembodiments, the proximal actuation assembly 332 is operatively coupledwith the end effector base so as to selectively reorient the endeffector base relative to the main shaft 334 in two dimensions vialinked tension members as described above with regard to the surgicaltools 170, 260, and is operatively coupled with the end effector 336 soas to articulate one or more end effector features relative to the endeffector base. A variety of actuation components can be used to couplethe actuation assembly 332 with the end effector 336, for example,control cables, drive shafts, and the above described linked tensionmembers and corresponding end effector base attachment features. In manyembodiments, the actuation components are routed between the actuationassembly 332 and the end effector 336 through a bore of the main shaft334.

The tool assembly 330 can be configured for use in a variety ofapplications, for example, as a hand held device with manual and/orautomated actuation used in the proximal actuation mechanism 332. Assuch, the tool assembly 330 can have applications beyond minimallyinvasive robotic surgery, for example, non-robotic minimally invasivesurgery, non-minimally invasive robotic surgery, non-roboticnon-minimally invasive surgery, as well as other applications where theuse of a two degree-of-freedom joint articulated by linked tensionmembers would be beneficial.

Mechanisms For Transmitting Torque Through an Angle

FIG. 17 is a simplified diagrammatic illustration of a tool assembly 370having a mechanism 372 for transmitting torque through an angle, inaccordance with many embodiments. The tool assembly 370 includes aproximal torque source 374, a main shaft 376, an articulated endeffector base of an end effector 378, and the torque transmittingmechanism 372. The torque transmitting mechanism 372 includes a driveshaft 380, a driven shaft 382, and a coupling member 384 coupled withboth the drive shaft 380 and the driven shaft 382 such that a rotationof the drive shaft 380 produces a corresponding rotation of the drivenshaft 382. In many embodiments, the drive shaft 380 is mounted forrotation relative to the main shaft 376 and is routed through a bore(centerline or offset) of the main shaft 376. In many embodiments, thetorque transmitting mechanism 372 is configured so that the speed ofrotation of the driven shaft 382 substantially matches the speed ofrotation of the drive shaft 380 at any relative angular orientationbetween the shafts. In operation, the proximal torque source 374 rotatesthe drive shaft 380, which rotates the coupling member 384, whichrotates the driven shaft 382, thereby transmitting torque through anangle between the main shaft 376 and the end effector 378. In manyembodiments, the driven shaft 382 actuates a shaft driven mechanism ofthe end effector 378. For example, an end effector shaft drivenmechanism can articulate a clamping jaw relative to the articulated endeffector base and/or can actuate a surgical device (e.g., a staplingdevice, a cutter device, a cautery device). Such shaft driven mechanismsare merely exemplary. The driven shaft can be used to actuate othersuitable shaft driven mechanisms. Additionally, while the tool assembly370 is shown with one torque transmitting mechanism 372, this is merelyexemplary. One or more torque transmitting mechanisms 372 can be used,for example, to transfer torque from the proximal torque source 374 to acorresponding one or more end effector mechanisms.

The tool assembly 370 can be configured for use in a variety ofapplications, for example, as a hand held device with manual and/orautomated actuation used in the proximal torque source 374. As such, thetool assembly 370 can have applications beyond minimally invasiverobotic surgery, for example, non-robotic minimally invasive surgery,non-minimally invasive robotic surgery, non-robotic non-minimallyinvasive surgery, as well as other applications where the use of thedisclosed mechanisms for transmitting torque through an angle would bebeneficial.

FIG. 18 is a side view of a mechanism 390 for transmitting torquethrough an angle, in accordance with many embodiments. The torquetransmitting mechanism 390 includes a drive shaft 392, a coupling member394, a driven shaft 396, a first coupling pin 398, and a second couplingpin 400. FIG. 18 illustrates the torque transmitting mechanism 390 in aninline configuration.

The drive shaft 392 is axially and rotationally coupled with thecoupling member 394. The drive shaft 392 has a distal end 402 that isreceived within a first receptacle 404 of the coupling member 394. Thedrive shaft distal end 402 comprises a transverse slot 406. The firstcoupling pin 398 mates with the coupling member 394 so as to cross thefirst receptacle 404. The first coupling pin 398 is received by thedrive shaft transverse slot 406. The drive shaft distal end 402 and thecoupling member first receptacle 404 can have a complementary shapedinterfacing surface(s), for example, a spherical surface(s). Interactionbetween the first coupling pin 398 and the drive shaft transverse slot404 axially and rotationally couples the drive shaft 392 and thecoupling member 394. Additionally, interaction between interfacingsurfaces of the drive shaft distal end 402 and the coupling member firstreceptacle 404 can further restrain the drive shaft 392 relative to thecoupling member 394.

Similarly, the driven shaft 396 is axially and rotationally coupled withthe coupling member 394. The driven shaft 396 has a proximal end 408that is received within a second receptacle 410 of the coupling member394. The driven shaft proximal end 408 comprises a transverse slot 412.The second coupling pin 400 mates with the coupling member 394 so as tocross the second receptacle 410. The second coupling pin 400 is receivedby the driven shaft transverse slot 412. The driven shaft proximal end408 and the coupling member second receptacle 410 can have acomplementary shaped interfacing surface(s), for example, a sphericalsurface(s). Interaction between the second coupling pin 400 and thedriven shaft transverse slot 412 axially and rotationally couples thedriven shaft 396 and the coupling member 394. Additionally, interactionbetween interfacing surfaces of the driven shaft proximal end 408 andthe coupling member second receptacle 410 can further restrain thedriven shaft 396 relative to the coupling member 394.

FIG. 19a is a cross-sectional view of the torque transmitting mechanism390 of FIG. 18, illustrating engagement between spherical gear teeth 414of the drive shaft 392 and mating spherical gear teeth 416 of the drivenshaft 396, in accordance with many embodiments. The gear teeth aretermed “spherical” because they are in the general form of geometricsmall circles on a sphere's surface. The cross section illustratedincludes the centerlines of the drive shaft 392, the driven shaft 396,and the coupling member 394, respectively, and is taken along a viewdirection parallel to the first coupling pin 398 and the second couplingpin 400. In the inline configuration illustrated, the coupling member394, the drive shaft 392, and the driven shaft 396 are aligned. Thecoupling member 394 rotates about a coupling member axis 418. Thecoupling member axis 418 is a longitudinal centerline between the tworeceptacles 404, 410. The drive shaft 392 rotates about a drive axis420. The driven shaft 396 rotates about a driven axis 422. The driveshaft 392 is constrained to pivot about the first coupling pin 398 (andthereby is constrained to pivot relative to the coupling member 394).Likewise, the driven shaft 396 is constrained to pivot about the secondcoupling pin 400 (and thereby is constrained to pivot relative to thecoupling member 394). The additional constraint between the drive shaft392 and the driven shaft 396 provided by the engagement between thedrive shaft gear teeth 414 and the driven shaft gear teeth 416 ties therelative angular orientation between the drive shaft 392 and thecoupling member 394 to the relative angular orientation between thedriven shaft 396 and the coupling member 394.

FIG. 19a also illustrates a drive shaft outer spherical surface 424 thatinterfaces with an inner spherical surface 426 of the coupling memberfirst receptacle 404. Similarly, a driven shaft outer spherical surface428 interfaces with an inner spherical surface 430 of the couplingmember second receptacle 410. As discussed above, the constraintprovided by the first coupling pin 398 axially and rotationally couplesthe drive shaft 392 and the coupling member 394, and the constraintprovided by the second coupling pin 400 axially and rotationally couplesthe driven shaft 396 and the coupling member 394. Additionally, theconstraint provided by the interfacing spherical surfaces can furtherconstrain the drive shaft 392 and the driven shaft 396 relative to thecoupling member 394.

FIG. 19b is a cross-sectional view of the torque transmitting mechanism390 of FIGS. 18 and 19 a, illustrating engagement between the driveshaft gear teeth 414 and the driven shaft gear teeth 416 for an angledconfiguration, in accordance with many embodiments. The cross sectionillustrated includes the drive axis 420, the driven axis 422, and thecoupling member axis 418, and is taken along a view direction parallelto the first coupling pin 398 and the second coupling pin 400.

In the angled configuration illustrated, the driven axis 422 deviatesfrom the drive axis 420 by 70 degrees. The constraint provided byengagement between the drive shaft gear teeth 414 and the driven shaftgear teeth 416 results in the 70 degrees being equally distributedamongst a 35 degree deviation between the drive axis 420 and thecoupling axis 418, and a 35 degree deviation between the coupling axis418 and the driven axis 422. By constraining the coupling member to beoriented at an equivalent relative angle to both the drive shaft and thedriven shaft, any rotational speed differences between the drive shaftand the coupling member are effectively canceled when the rotation ofthe coupling member is transferred to the driven shaft, therebysubstantially eliminating any rotational speed differences between thedrive shaft and the driven shaft.

The drive shaft gear teeth 414 and the driven shaft gear teeth 416 arespherically oriented so as to provide the above described constraintbetween the drive shaft 392 and the driven shaft 396 for any angularorientation of the torque transmitting mechanism 390. For an angledconfiguration, rotation of the drive shaft 392 and a correspondingrotation of the driven shaft 396 causes different portions of the driveshaft distal end 402 and the driven shaft proximal end 408 to beintersected by the coupling axis 418. The use of spherical gear teethallows this movement of the shafts while still providing the angularconstraint necessary to orient the coupling member relative to the driveshafts.

Other suitable shaft angle constraint configurations can also be used.For example, as illustrated in FIG. 19c , a drive shaft feature (e.g., afeature comprising a spherical surface 432 cantilevered from the driveshaft distal end) can engage with a driven shaft feature (e.g., afeature comprising a cylindrical bore 434 receiving the cantilevereddrive shaft feature comprising a spherical surface cantilevered from thedriven shaft proximal end). While the use of some shaft angleconstraints may result in some level of variation between a relativeangle between the drive axis 420 and the coupling axis 418, and arelative angle between the coupling axis 418 and the driven axis 422,the resulting rotational speed variations between the drive shaft 392and the driven shaft 396 may be acceptable in some applications.

Other spherical gear tooth profiles can be used to provide a suitableshaft angle constraint. For example, the drive shaft distal end 402 cancomprise a gear tooth surface that extends around the drive axis 420 andthe driven shaft proximal end 408 can comprise a complementary geartooth surface that extends around the driven axis 422 so that the driveshaft gear tooth surface engages the driven shaft gear tooth surface soas to provide the shaft angle constraint. The drive shaft gear toothsurface can be defined by a drive shaft gear tooth profile extendingradially from the drive axis 420 and the driven shaft gear tooth surfacecan be defined by a driven shaft gear tooth profile extending radiallyfrom the driven axis 422 so as to provide a shaft angle constraint thatmaintains substantial equivalence between the drive/coupler angle andthe driven/coupler angle. The drive shaft gear tooth surface cancomprise a revolute surface defined by rotating the drive shaft geartooth profile about the drive axis 420 and the driven shaft gear toothsurface can comprise a revolute surface defined by rotating the drivenshaft gear tooth profile about the driven axis 422. For example, in FIG.19c , the cantilevered spherical surface 432 includes a gear toothprofile (its circular cross section) that extends radially from thedrive axis and a revolute surface defined by rotating its gear toothprofile about the drive axis 420. The cylindrical bore surface 434includes a complementary gear tooth surface (its straight line crosssection) that extends radially from the driven axis 422 and a revolutesurface defined by rotating its gear tooth profile about the drive axis422. Other gear tooth profiles can be configured in a like fashion, forexample, gear tooth profiles intermediate in shape between the geartooth profile illustrated in FIG. 19a and the gear tooth profileillustrated in FIG. 19 c.

FIG. 19d is a cross-sectional view of the torque transmitting mechanism390 of FIGS. 18, 19 a, and 19 b, illustrating the configuration of thedrive shaft transverse slot 406 and the similar driven shaft transverseslot 412, in accordance with many embodiments. The drive shafttransverse slot 406 is configured to accommodate the first coupling pin398 throughout a range of angles between the drive axis 420 and thecoupling axis 418. Likewise, the driven shaft transverse slot 412 isconfigured to accommodate the second coupling pin 400 throughout a rangeof angles between the driven axis 422 and the coupling axis 418. Whenthe torque transmitting mechanism 390 is operated in an angledconfiguration, the position of the first coupling pin 398 within thedrive shaft transverse slot 406 will undergo a single oscillation cyclefor each 360 degree rotation of the drive shaft 392. Likewise, theposition of the second coupling pin 400 within the driven shafttransverse slot 412 will undergo a single oscillation cycle for each 360degree rotation of the driven shaft 396.

FIG. 20 presents an assortment of perspective views of the drive shaft392 and the driven shaft 396. These perspective views show details ofthe drive and driven shafts from different viewing directions, forexample, the spherical gear teeth 414 of the drive shaft 392, thespherical gear teeth 416 of the driven shaft 396, the drive shafttransverse slot 406, the driven shaft transverse slot 412, the driveshaft outer spherical surface 424, and the driven shaft outer sphericalsurface 428.

The oscillation of the coupling pins 398, 400 within the transverseslots 406, 412 can be described with reference to FIGS. 21a and 21b .FIG. 21a is a view of the torque transmitting mechanism 390 along a viewdirection normal to the coupling pins 398, 400. FIG. 21b is a view ofthe torque transmitting mechanism 390 along a view direction parallel tothe coupling pins 398, 400. In FIGS. 21a and 21b , the coupling member394 is transparent to illustrate interactions between mechanismcomponents. In the position shown in FIG. 21a , to accommodate the anglebetween the drive shaft 392 and the coupling member 394, the firstcoupling pin 398 is canted within the drive shaft transverse slot (thiscan be visualized by considering the slot shape illustrated in FIG. 19din conjunction with the shaft angles illustrated in FIG. 21a ). In FIG.21b , the coupling member 394 has an angular orientation that is 90degrees from the coupling member orientation of FIG. 21a , therebyaligning the coupling pins 398, 400 with the view direction. For theorientation shown in FIG. 21b , the coupling pins 398, 400 are notcanted within the transverse slots 406, 412 (similar to FIG. 19d ).During a 360 degree revolution of the torque transmitting mechanism 390,the position of the coupling pins 398, 400 within the transverse slots406, 412 will complete an oscillation cycle.

In the torque transmitting mechanism 390, with respect to each other,the rotating shafts and the coupling each have a “yaw” degree-of-freedom(DOF) around the associated pin's longitudinal centerline and a “pitch”DOF around a line perpendicular to the pin's longitudinal centerline.The two “yaw” axes are parallel, and the “pitch” axes are constrained byengagement between the rotating shaft to each be one-half the totalangle between the driving and driven shafts.

Multiple rows of spherical gear teeth can be used to couple the driveand driven shafts so as to provide shaft angle constraint. For example,FIG. 22a illustrates multiple rows of interfacing spherical gear teeth.FIG. 22b illustrates the cross-sectional profile and sphericalarrangement of the gear teeth of FIG. 22 a.

FIG. 23a is a side view of a mechanism 440 for transmitting torquethrough an angle, in accordance with many embodiments. The torquetransmitting mechanism 440 is similar to the mechanism 390 describedabove, but has a double cross pin configuration. For example, themechanism 440 uses the same coupling member 394 and the same couplingpins 398, 400 as the mechanism 390, but incorporates a drive shaft crosspin 442 to couple a drive shaft 444 with the coupling pin 398, and adriven shaft cross pin 446 to couple a driven shaft 448 with thecoupling pin 400. In FIG. 23a , a “see through” coupling member 394 isshown to better illustrate details of the double cross pinconfiguration.

FIG. 23b shows the mechanism 440 with the coupling member 394 removedand a “see through” driven shaft 448 to better illustrate the drivenshaft cross pin 446. The driven shaft cross pin 446 is received within abore of the driven shaft 448 and is rotatable within the driven shaftbore. The coupling pin 400 is received within a bore of the driven shaftcross pin 446. Relative rotation between the driven shaft 448 and thecoupling member 394 about the centerline of the coupling pin 400 occursvia rotation of the coupling pin 400 relative to the coupling member 394and/or rotation of the coupling pin 400 relative to the driven shaftcross pin 446. Similarly, the drive shaft cross pin 442 is receivedwithin a bore of the drive shaft 444 and it is rotatable within thedrive shaft bore. The coupling pin 398 is received within a bore of thedrive shaft cross pin 442. Relative rotation between the drive shaft 444and the coupling member 394 about the centerline of the coupling pin 398occurs via rotation of the coupling pin 398 relative to the couplingmember 394 and/or rotation of the coupling pin 398 relative to the driveshaft cross pin 442.

FIG. 23c is a cross-sectional view of the mechanism 440 of FIGS. 23a and23b taken through the centerlines of the coupling pins 398, 400. Thedrive shaft transverse slot 406 is configured to accommodate thecoupling pin 398 throughout a range of angles between the drive shaft444 and the coupling member 394 that occurs via rotation of the driveshaft 444 relative to the centerline of the drive shaft cross pin 442.Similarly, the driven shaft transverse slot 412 is configured toaccommodate the coupling pin 400 throughout a range of angles betweenthe driven shaft 448 and the coupling member 394 that occurs viarotation of the driven shaft 448 relative to the centerline of thedriven shaft cross pin 446. As can be seen by comparing FIG. 23c to FIG.19d , the double cross pin configuration of the mechanism 440 providesfor reduced mechanism free-play along the drive and driven shafts ascompared to the single cross pin configuration of the mechanism 390.Such reduced free-play may provide more consistent coupling between thedrive shaft gear teeth 414 and the driven shaft gear teeth 416.

FIG. 23d shows the cross pin receiving bore 450 of the drive shaft 444and the similar cross pin receiving bore 452 of the driven shaft 448.FIG. 23e shows the drive shaft transverse slot 406 and the driven shafttransverse slot 412.

FIG. 24a is a simplified diagrammatic illustration of a mechanism 460for transmitting torque through an angle in which shaft protrusionsinteract with coupling member slots to transfer rotational motion, inaccordance with many embodiments. The torque transmitting mechanism 460includes the drive shaft 462, a coupling member 464, and a driven shaft466.

The drive shaft 462 is configured to axially and rotationally couplewith the coupling member 464. The drive shaft 462 has a proximal end468, a distal end 470, and a drive axis 472 defined there between. Thedrive shaft 462 includes a first cylindrical protrusion 474 protrudingfrom the drive shaft distal end 470 and a second cylindrical protrusion476 protruding from an opposing side of the drive shaft distal end 470.The drive shaft distal end 470 has a spherical surface 478 and sphericalgear teeth 480.

Similarly, the driven shaft 466 is configured to axially androtationally couple with the coupling member 464. The driven shaft 466has a distal end 482, a proximal end 484, and a driven axis 486 definedthere between. The driven shaft 466 includes a third cylindricalprotrusion 488 protruding from the driven shaft proximal end 484 and afourth cylindrical protrusion 490 protruding from an opposing side ofthe driven shaft proximal end 484. The driven shaft proximal end 484 hasa spherical surface 492 and spherical gear teeth 494.

The coupling member 464 is configured to axially couple with both thedrive shaft distal end 470 and the driven shaft proximal end 484. Thecoupling member 464 has a tubular structure defining a drive receptacle496, a driven receptacle 498, and a coupling axis 500 defined therebetween. The drive receptacle 496 is shaped to interface with the driveshaft distal end 470 so as to create a ball joint constraint between thedrive shaft distal end 470 and the drive receptacle 496. For example,the drive receptacle 496 can include one or more surfaces configured tointerface with the drive shaft distal end spherical surface 478. In manyembodiments, the drive receptacle 496 includes a spherical surface 502configured to interface with the drive shaft distal end sphericalsurface 478. Similarly, the driven receptacle 498 is shaped to interfacewith the driven shaft proximal end 484 so as to create a ball jointconstraint between the driven shaft proximal end 484 and the drivenreceptacle 498. For example, the driven receptacle 498 can include oneor more surfaces configured to interface with the driven shaft proximalend spherical surface 492. In many embodiments, the driven receptacle498 includes a spherical surface 504 configured to interface with thedriven shaft proximal end spherical surface 492. As described in moredetail below, the coupling member 464 can include one or more separatepieces, for example, two pieces.

The coupling member 464 is also configured to rotationally couple withboth the drive shaft distal end 470 and the driven shaft proximal end484. The coupling member first receptacle 496 includes a first slot 506and a second slot 508. The first slot 506 and the second slot 508 areconfigured to receive the first protrusion 474 and the second protrusion476, respectively, and accommodate the protrusions 474, 476 throughout arange of angles between the drive shaft 462 and the driven shaft 466 (asillustrated in FIG. 24d ). Similarly, the coupling member secondreceptacle 498 includes a third slot 510 and a fourth slot 512. Thethird slot 510 and the fourth slot 512 are configured to receive thethird protrusion 488 and the fourth protrusion 490, respectively, andaccommodate the protrusions 488, 490 throughout a range of anglesbetween the drive shaft 462 and the driven shaft 466. Interactionbetween the drive shaft protrusions 474, 476 and the first receptacleslots 506, 508 transfers rotational motion from the drive shaft 462 tothe coupling member 464. Similarly, interaction between the secondreceptacle slots 510, 512 and the driven shaft protrusion 488, 490transfers rotational motion from the coupling member 464 to the drivenshaft 466.

The torque transmitting mechanism 460 uses engagement between the driveshaft distal end 470 and the driven shaft proximal end 484 to controlthe relative angular orientations of the drive shaft 462, the couplingmember 464, and the driven shaft 466. Engagement features, for example,the spherical gear teeth 480, 494, can be used to control the relativeorientations of the drive shaft 462, the coupling member 464, and thedriven shaft 466. While the shaft angle constraint between the driveshaft 462 and the driven shaft 466 is provided by meshing spherical gearteeth 480, 494 in the torque transmitting mechanism 460, the use ofspherical gear teeth is merely exemplary. Other suitable shaft angleconstraints can also be used, for example, the shaft angle constraintsfor the torque transmitting mechanism 390 discussed above can also beused in the torque transmitting mechanism 460. Additionally, the geartooth definitions applicable to the above discussed torque transmittingmechanism 390 are also applicable to the torque transmitting mechanism460.

FIG. 24b is a view of the torque transmitting mechanism 460 of FIG. 24aalong a view direction parallel to the protrusions, in accordance withmany embodiments. Hidden lines illustrate the first protrusion 474within the first slot 506 and the third protrusion 488 within the thirdslot 510. The elongated shape of the slots enables the drive shaft 462and the driven shaft 466 to pivot relative to the coupling member 464while providing for the transfer of rotational motion between the driveshaft 462 and the coupling member 464, and between the coupling member464 and the driven shaft 466.

FIG. 24c is a view of the torque transmitting mechanism 460 of FIGS. 24aand 24b along a view direction normal to the protrusions, illustratingdetails of a two piece coupling member 464, in accordance with manyembodiments. The coupling member 464 includes a first piece 514 and asecond piece 516. The first piece 514 and the second piece 516 includeattachment flanges 518 having fastener holes for attachment fasteners(not shown). Although the coupling member 464 is shown as including thefirst piece 514 and the second piece 516 that are shown as being joinedvia attachment flanges 518, this approach is merely exemplary and othersuitable approaches can be used. For example, the coupling member 464can be split into a central tubular piece and two adjoining end capsthat can be assembled to the central tubular piece after the drive shaft462 and the driven shaft 466 are positioned relative to the centraltubular piece.

FIG. 24d illustrates the torque transmitting mechanism 460 of FIGS. 24a,24b, and 24c in an angled configuration, in accordance with manyembodiments. The spherical gear teeth 480, 494, in conjunction with thepositional constraint provided by the interface between the drive shaftdistal end 470 and the coupling member first receptacle 496, and thepositional constraint provided by the interface between the driven shaftproximal end 484 and the coupling member second receptacle 498,constrain the torque transmitting mechanism 460 so that the anglebetween the drive axis 472 and the coupling axis 500 is substantiallyequivalent to the angle between the coupling axis 500 and the drivenaxis 486. In operation, rotation of the drive shaft 462 about the driveaxis 472 produces rotation of the coupling member 464 about the couplingaxis 500 via interaction between the first protrusion 474 and the firstslot 506, and interaction between the second protrusion 476 and thesecond slot 508. In operation, the position of the protrusions 474, 476within the slots 506, 508 oscillates in a manner similar to theoscillation of the coupling pins 398, 400 discussed above with referenceto the torque transmitting mechanism 390 of FIG. 18 through FIG. 21b .Similarly, rotation of the coupling member 464 about the coupling axis500 produces rotation of the driven shaft 466 about the driven axis 486.

FIGS. 25a and 25b are simplified diagrammatic illustrations of amechanism 520 for transmitting torque through an angle in which modifiedU-joint coupling members transfer rotational motion between a driveshaft and a coupling member and between the coupling member and a drivenshaft, in accordance with many embodiments. The torque transmittingmechanism 520 includes a drive shaft 522, a first modified U-jointcoupling 524, a coupling member 526, a second modified U-joint coupling528, and a driven shaft 530. As with the above described embodiments,the torque transmitting mechanism 520 employs drive shaft and drivenshaft engagement features (e.g., spherical gear teeth 532, 534) toconstrain the relative orientations of the drive shaft 522, the couplingmember 526, and the driven shaft 530.

The modified U-joint couplings 524, 528 axially and rotationally couplethe drive shaft 522 to the coupling member 526, and the coupling member526 to the driven shaft 530, respectively. The first modified U-jointcoupling 524 includes a first pin 536 and a second pin 538. The firstpin 536 is mounted for rotation relative to the coupling member 526about a first pin axis 540. The second pin 538 is oriented transverse tothe first pin 536 and is coupled with the first pin 536. The drive shaft522 is coupled with the second pin 538 to rotate about a second pin axis542. The second pin axis 542 itself rotates about the first pin axis540. The drive shaft 522 includes an opening 544 configured toaccommodate the first pin 536. Similarly, the second modified U-jointcoupling 528 includes a third pin 546 and a fourth pin 548. The thirdpin 546 is mounted for rotation relative to the coupling member 526about a third pin axis 550. The fourth pin 548 is oriented transverse tothe third pin 546 and is coupled with the third pin 546. The drivenshaft 530 is coupled with the fourth pin 548 to rotate about a fourthpin axis 552. The fourth pin axis 552 itself rotates about the third pinaxis 550. The driven shaft 530 includes an opening 554 configured toaccommodate the third pin 546. The coupling member 526 can includeopenings 556 that provide for installation of the second pin 538 and thefourth pin 548.

In operation, the torque transmitting mechanism 520 functions similarlyto the torque transmitting mechanisms 390, 460 set forth above. Thedrive shaft and driven shaft engagement features (e.g., spherical gearteeth 532, 534) constrain the relative orientations of the drive shaft522, the coupling member 526, and the driven shaft 530 so that relativeangles between the drive shaft 522 and the coupling member 526, andbetween the coupling member 526 and the driven shaft 530 aresubstantially equal. In operation, rotation of the drive shaft 522produces rotation of the coupling member 526 via the first modifiedU-joint coupling 524. Similarly, rotation of the coupling member 526produces rotation of the driven shaft 530 via the second modifiedU-joint coupling 528.

Combined Features

FIG. 26 illustrates a compact wrist 600 having a two degree-of-freedomwrist that is articulated by linked tension members as disclosed herein,as well as the use of double universal joints as disclosed herein totransmit torque through an angle across the two degree-of-freedom wrist.The compact wrist 600 integrates a two degree-of-freedom wrist, wristarticulation by linked tension members, and torque transmission throughan angle by double universal joints. While all three of these aspectsare included in the compact wrist 600, a wrist can utilize any of theaspects disclosed herein individually or in any suitable combination. Abenefit of these three combined aspects is an ability to transmitoff-centerline torque through a two degree-of-freedom wrist mechanismwith a large angular displacement capability (e.g., up to about 60degrees in any direction) and relatively short length. In a minimallyinvasive surgical environment (e.g., during bowel surgery), such a shortlength wrist mechanism allows a surgical end effector that requires thetransmitted torques for operation to be maneuvered (pitched, yawed,rolled) in tight spaces, so that the lateral distance between thearticulated end effector and the distal end of the supporting shaft isminimized. The descriptions above have concentrated on describingparticular aspects and features. It should be understood, however, thatvarious aspects and features may be combined whenever practical. Thatis, particular aspects and features described above with reference toone embodiment may be incorporated into one or more other embodiments,even though such alternate embodiments are not specifically shown.

It is understood that the examples and embodiments described herein arefor illustrative purposes and that various modifications or changes inlight thereof will be suggested to persons skilled in the art and are tobe included within the spirit and purview of this application and thescope of the appended claims. Numerous different combinations arepossible, and such combinations are considered to be part of the presentinvention.

What is claimed is:
 1. A surgical tool comprising: an elongate shaftextending along a longitudinal axis and having a proximal end and adistal end, the longitudinal axis extending through the proximal anddistal ends; and an end effector movably coupled to the distal end ofthe elongate shaft to rotate about a first axis and a second axis, thefirst axis being orthogonal to the longitudinal axis, the second axisbeing orthogonal to the first axis and transverse to the longitudinalaxis, the second axis being offset from the first axis along thelongitudinal axis, the end effector including four attachment features,each of the four attachment features including a curved portion, each ofthe four curved portions having a center-of-curvature and a curvedordinary centerline, each of the four center-of-curvatures being locatedin a plane containing the second axis, and each of the four curvedordinary centerlines being tangent to a plane containing the first axis.2. The surgical tool of claim 1, wherein each of the four curvedportions comprises a segment of a solid torus having the respectivecenter-of-curvature as the axis of revolution of the solid torus and therespective curved ordinary centerline passes through cross-sectionalcenters of the respective curved portion.
 3. The surgical tool of claim1, further comprising four tension members extending along the elongateshaft, each of the four tension members being interfaced with arespective one of the four curved portions and configured to: slidealong the respective curved portion in conjunction with rotation of theend effector about the second axis; and rotate around the respectivecurved ordinary centerline in conjunction with rotation of the endeffector about the first axis.
 4. The surgical tool of claim 3, whereineach of the four tension members comprises a lug having an aperturethrough which the respective curved portion extends.
 5. The surgicaltool of claim 3, wherein the four tension members are arranged aroundthe longitudinal axis in a first diagonally opposed pair and a seconddiagonally opposed pair, each of the four tension members being undertension induced by a force applied to the tension member and transferredto the respective one of the attachment features by the tension member.6. The surgical tool of claim 5, wherein: rotation of the end effectorabout the first axis occurs in conjunction with proximal displacement ofone of each of the first and second diagonally opposed pairs of thetension members that the is equal in magnitude to distal displacement ofthe other of each of the first and second diagonally opposed pairs ofthe tension members; and rotation of the end effector about the secondaxis occurs in conjunction with proximal displacement of one of each ofthe first and second diagonally opposed pairs of the tension membersthat the is equal in magnitude to distal displacement of the other ofeach of the first and second diagonally opposed pairs of the tensionmembers.
 7. The surgical tool of claim 1, wherein the first and secondaxes are separated by 2 mm or less.
 8. The surgical tool of claim 1,further comprising an intermediate member pivotally coupled with theelongate shaft to rotate relative to the elongate shaft about the firstaxis, the intermediate member being pivotally coupled with the endeffector so that the end effector rotates relative to the intermediatemember about the second axis.
 9. The surgical tool of claim 8, wherein:the elongate shaft comprises a support member to which the intermediatemember is pivotally coupled to rotate about the first axis; angularrotation of the intermediate member relative to the elongate shaft aboutthe first axis is limited via contact between the intermediate memberand the support member; and angular rotation of the end effector aboutthe second axis is limited via contact between the end effector and theintermediate member.
 10. The surgical tool of claim 8, wherein theintermediate member has internal passages shaped to constraincross-sectional positions of control cables of an actuation system. 11.A surgical instrument for use with a robotic manipulator of a minimallyinvasive surgical system, the robotic manipulator having a holdingfixture, the surgical instrument comprising: an elongate shaft having aproximal end and a distal end, wherein a longitudinal axis extendsthrough the proximal and distal ends; a chassis disposed at the proximalend and holding the elongate shaft, the chassis being configured to bemounted to the holding fixture; an end effector movably coupled to thedistal end of the elongate shaft to rotate about a first axis and asecond axis, the first axis being orthogonal to the longitudinal axis,the second axis being orthogonal to the first axis and transverse to thelongitudinal axis, the second axis being offset from the first axisalong the longitudinal axis, the end effector including four attachmentfeatures, each of the four attachment features including a curvedportion, each of the four curved portions having a center-of-curvatureand a curved ordinary centerline, each of the four center-of-curvaturesbeing located in a plane containing the second axis, and each of thefour curved ordinary centerlines being tangent to a plane containing thefirst axis; and four tension members extending along the elongate shaftbetween the chassis and the end effector, each of the four tensionmembers being interfaced with a respective one of the four curvedportions and configured to: slide along the respective curved portion inconjunction with rotation of the end effector about the second axis; androtate around the respective curved ordinary centerline in conjunctionwith rotation of the end effector about the first axis.
 12. The surgicalinstrument of claim 11, wherein each of the four curved portionscomprises a segment of a solid torus having the respectivecenter-of-curvature as the axis of revolution of the solid torus and therespective curved ordinary centerline passes through cross-sectionalcenters of the respective curved portion.
 13. The surgical instrument ofclaim 11, wherein each of the four tension members comprises a lughaving an aperture through which the respective curved portion extends.14. The surgical instrument of claim 11, wherein the four tensionmembers are arranged around the longitudinal axis in a first diagonallyopposed pair and a second diagonally opposed pair, each of the fourtension members being under tension induced by a force applied to thetension member and transferred to the respective one of the attachmentfeatures by the tension member.
 15. The surgical instrument of claim 14,wherein: rotation of the end effector about the first axis occurs inconjunction with proximal displacement of one of each of the first andsecond diagonally opposed pairs of the tension members that the is equalin magnitude to distal displacement of the other of each of the firstand second diagonally opposed pairs of the tension members; and rotationof the end effector about the second axis occurs in conjunction withproximal displacement of one of each of the first and second diagonallyopposed pairs of the tension members that the is equal in magnitude todistal displacement of the other of each of the first and seconddiagonally opposed pairs of the tension members.
 16. The surgicalinstrument of claim 11, wherein the first and second axes are separatedby 2 mm or less.
 17. The surgical instrument of claim 11, furthercomprising an intermediate member pivotally coupled with the elongateshaft to rotate relative to the elongate shaft about the first axis, theintermediate member being pivotally coupled with the end effector sothat the end effector rotates relative to the intermediate member aboutthe second axis.
 18. The surgical instrument of claim 17, wherein: theelongate shaft comprises a support member to which the intermediatemember is pivotally coupled to rotate about the first axis; angularrotation of the intermediate member relative to the elongate shaft aboutthe first axis is limited via contact between the intermediate memberand the support member; and angular rotation of the end effector aboutthe second axis is limited via contact between the end effector and theintermediate member.
 19. The surgical instrument of claim 17, whereinthe intermediate member has internal passages shaped to constraincross-sectional positions of control cables of an actuation system. 20.The surgical instrument of claim 11, further comprising a firstactuation mechanism at least partially disposed within the chassis and asecond actuation mechanism at least partially disposed within thechassis, the first actuation mechanism including a first rotatablecapstan drivingly coupled with a first diagonally opposed pair of thefour tension members, the second actuation mechanism including a secondrotatable capstan drivingly coupled with s second diagonally opposedpair of the four tension members, and wherein controlled rotation ofeach of the first and second capstans is used to angularly reorient theend effector about the first and second axes.